During the Second World War, a large house on a hill overlooking Cairns became one of Australia’s most secret military establishments.
Fairview House at Mooroobool, known to wartime personnel simply as the “House on the Hill”, became the headquarters of the Z Experimental Station, or ZES. Established in 1942, it is remembered primarily for its association with Australian special operations and Z Special Unit, including preparations connected with Operation Jaywick, the celebrated raid on Japanese shipping in Singapore Harbour.
But this familiar Australian story overlooks another important part of the station’s history.
Dutch and Indonesian personnel from the Netherlands East Indies were involved at ZES from its earliest period. After a major reorganisation of Allied intelligence in 1943, the facility increasingly became a training, communications, holding and operational staging centre for NEFIS III, the clandestine intelligence and special-operations section of the Netherlands Forces Intelligence Service.
From Cairns, Dutch and Indonesian operatives were trained and prepared for missions back into Japanese-occupied territory.
The House on the Hill was therefore not simply an Australian commando school. For an important period of the Pacific War it became a centre of Dutch-Australian-Indonesian intelligence cooperation.
Why Cairns?
Z Experimental Station was established at Fairview Farm, Mooroobool, in June–July 1942.
The site was selected partly because of its excellent wireless reception. It was sufficiently isolated from Cairns to provide some security and was strategically well placed for operations moving north towards New Guinea and the Netherlands East Indies.
The station was initially associated with Secret Intelligence Australia (SIA) and the Inter-Allied Services Department (ISD). These were distinct organisations: SIA was connected with Britain’s Secret Intelligence Service, or SIS/MI6, while ISD was concerned particularly with clandestine special operations.
Peter Dunn’s research identifies Commander Roy Kendall, head of SIA, as playing an important role in selecting the location.
At ZES, operatives could be trained in weapons, demolitions, signals, sea and jungle operations and clandestine communications. Personnel awaiting missions could also be held there, while equipment arriving from southern Australia could be assembled before men and supplies were moved forward by submarine, aircraft or other transport.
The station was therefore much more than a training school. It formed part of the operational infrastructure supporting the secret war north of Australia.
The Netherlands East Indies was involved from the beginning
The Dutch and Indonesian presence at ZES did not begin only after NEFIS formally took greater control in 1943.
Personnel from the Netherlands East Indies were already deeply involved during the earlier ISD period.
Research based on surviving ISD records shows that by December 1942 its operational personnel included 27 Australians and 53 Dutch or NEI personnel. Altogether, 71 NEI personnel were attached to ISD, including Dutch and Indonesian soldiers, sailors, police, wireless operators, mechanics and other specialists. Personnel were distributed between Melbourne, Darwin, Cairns and other operational facilities.
Peter Dunn’s reconstruction of ZES indicates that Australians and NEI personnel were present at Cairns in roughly equal numbers during this early period and that a large majority of the NEI personnel were Indonesian.
That exact proportion is difficult to verify independently because many original ZES records were destroyed when ISD was disbanded. Nevertheless, the surviving evidence leaves little doubt that Indonesian personnel formed a substantial part of the Dutch/NEI presence at Cairns.
This is important. Describing ZES simply as a place where “Dutch personnel” trained risks obscuring the multinational character of the NEI forces themselves.
Julius Tahija — an Ambonese intelligence instructor in Queensland
One of the most remarkable people associated with ZES was Julius Tahija.
Tahija was an Ambonese officer of the Royal Netherlands East Indies Army, the KNIL. He had already experienced combat against the Japanese and later received the Militaire Willems-Orde, the Netherlands’ highest military decoration.
After reaching Australia, Tahija was attached to Z Experimental Station, where he became deputy intelligence instructor and helped train operatives in jungle survival and conditions they might encounter inside the Netherlands East Indies. Independent research identifies him as assistant to senior intelligence instructor Captain R.O.D. Noone.
Tahija subsequently participated in clandestine activities himself, including reconnaissance and work connected with local guerrillas and supply caches.
His presence at Cairns demonstrates how valuable personnel from the NEI could be.
Australian and British instructors could teach explosives, signals or military techniques. Men such as Tahija could also provide something more difficult to reproduce: knowledge of Indonesian societies, languages, climate, terrain and local behaviour.
This was exactly the sort of specialist knowledge that became increasingly important as Allied organisations attempted to send agents back into Japanese-occupied territory.
Early training was not always appropriate
The Cairns training system nevertheless had serious weaknesses.
Dutch historian Loe de Jong records that prospective agents destined for the Netherlands East Indies were trained at ZES in combat techniques, weapons and sabotage. But he also notes that in 1942 their training was not yet sufficiently adapted to the particular circumstances they would encounter in the NEI. Training in clandestine landings was also inadequate.
Australian military historian Dr Jack Ford reached a similar conclusion in his extensive study of the Dutch wartime presence in Australia, Allies in a Bind.
Ford records disastrous losses among several early NEFIS intelligence parties sent into Java and the Aroe Islands during 1943. Dutch intelligence chief Commander G.B. Salm blamed some of these failures on AIB training methods, which he believed were suitable for Australian conditions but not for the very different circumstances of the Netherlands East Indies.
These failures contributed to Dutch demands for greater control over their own intelligence operations and training.
MacArthur eventually granted NEFIS substantial control over training, codebreaking and the distribution of its intelligence. Ford records that a new six-month NEFIS training program was developed, including six weeks of strict isolation before an operational mission. Training was normally undertaken either at Cairns or at the joint NEFIS/AIB forward base in Darwin.
Cairns was therefore becoming increasingly important to the developing Dutch intelligence organisation.
Security and operational weaknesses
The problems at ZES were not limited to training methods.
Security was a persistent concern. Cairns had initially been attractive because of its relative isolation, but as the town became an increasingly important military assembly area, maintaining secrecy became more difficult. Personnel awaiting missions could remain at the station for long periods, sometimes for weeks, creating problems for morale and operational security.
Peter Dunn’s reconstruction of ZES also notes that shortages of instructors, equipment and transport initially hampered the station’s effectiveness. Many original ISD-era records were deliberately destroyed when the organisation was disbanded, making it difficult to reconstruct the full extent of these problems.
Later Dutch assessments were also critical of aspects of NEFIS preparation and security. Historian Rémy Limpach has argued that security at the Cairns training establishment was inadequate and that Japanese intelligence obtained useful information about NEFIS methods and personnel. He also points to poorly prepared operations in which agents were sometimes inadequately equipped or insufficiently prepared for the conditions they would encounter.
These problems had potentially lethal consequences. Intelligence agents entering Japanese-occupied territory depended on secrecy, suitable cover identities, appropriate clothing, local knowledge and secure communications. A weakness in any of these areas could expose an entire mission.
The shortcomings at Cairns should therefore be seen alongside the broader operational failures recorded by Jack Ford. They help explain why the Dutch increasingly pushed for greater control over NEFIS training and why later courses became longer, more specialised and more closely tailored to the conditions of the Netherlands East Indies.
Korps Insulinde comes to Australia
Another important source of experienced personnel was Korps Insulinde.
This was not an intelligence office but a Dutch commando formation.
Its origins lay partly among soldiers of the Princess Irene Brigade who had been sent from Britain towards Asia early in 1942. Following the Japanese conquest of the Netherlands East Indies, some remained in Ceylon, present-day Sri Lanka, where they received specialist training for operations behind Japanese lines.
Korps Insulinde was formally established in August 1942 and became one of the pioneering Dutch commando formations of the Second World War.
Jack Ford records that NEFIS obtained about 50 Korps Insulinde personnel from Ceylon. These men had already undergone intelligence and special-operations training at a British Special Operations Executive school in India. Another group remained in the Indian theatre under Major Mollinger.
The arrival of these men considerably strengthened the pool of trained personnel available to Dutch intelligence in Australia.
It also created a remarkable international chain.
Men originating in Dutch forces reorganised in Britain had been sent to Asia, trained in British facilities in Ceylon and India, transferred to Australia and then became involved with NEFIS operations directed back towards the Japanese-occupied Netherlands East Indies.
NEFIS III takes over the Cairns role
A major reorganisation of Allied clandestine organisations occurred in 1943.
ISD was dissolved and Australian special operations were reorganised into Special Operations Australia, later known under the cover name Services Reconnaissance Department or SRD.
Z Experimental Station did not simply follow SRD.
Instead, the Cairns establishment was handed over for use by NEFIS III, the Dutch secret-intelligence and special-operations section within the Allied Intelligence Bureau structure.
This is one of the most important facts about the history of the House on the Hill.
The Australian SRD increasingly developed its training facilities elsewhere, including Fraser Island. By September 1943, Cairns was regarded as unavailable to SRD because it had been taken over for Dutch/NEFIS purposes.
NEFIS III continued to train Indonesian operatives at ZES and use Cairns as a staging point for clandestine operations.
The popular description of Fairview House simply as a “Z Special Unit base” therefore tells only part of its history.
A Dutch intelligence training centre in Queensland
By 1944 the Dutch role was even clearer.
Surviving photographs associated with Jack Ford’s NEFIS research identify Major Mollinger at the Cairns ZES training centre and describe Lou Bierens de Haan as second-in-command. The material notes that secret agents were trained there for NEFIS.
Bierens de Haan himself had followed the remarkable route from the Princess Irene Brigade through Korps Insulinde to Australia and NEFIS III.
The Fairview establishment was therefore no longer merely hosting a few Dutch personnel inside an Australian training organisation. It had become an important part of the Dutch/NEI intelligence system operating from Australia.
This did not make ZES an exclusively Dutch establishment. Allied organisations continued to cooperate and share facilities and expertise. But the organisational balance had changed significantly from its beginnings in 1942.
From Cairns back into occupied territory
Training at Cairns was intended for a very practical purpose: preparing people to operate inside enemy-held territory.
These missions were extraordinarily dangerous.
Agents might have to land secretly from submarines or small vessels, move through communities under Japanese control, establish wireless communications, locate friendly contacts, collect intelligence and survive without conventional military support.
Many operations failed.
Ford records the loss of multiple parties attempting to penetrate Java and the Aroe Islands. Personnel were captured, disappeared or were executed by the Japanese. These losses eventually led NEFIS to change its methods, improve training and rethink the types of personnel who could successfully operate inside occupied territory.
Other operations were more successful.
In Dutch New Guinea, intelligence and guerrilla parties maintained resistance and provided information that later assisted MacArthur’s advancing forces. Ford notes that Dutch guerrillas around the Vogelkop region helped prevent complete Japanese control of local communities, which proved useful to Allied forces during their advance in 1944.
The Cairns school therefore formed one link in a much larger intelligence chain:
recruitment and selection in Australia; training and preparation at facilities such as ZES; insertion by submarine, aircraft or boat; intelligence collection inside occupied territory; wireless transmission back to Australia; and eventual use of that intelligence by Allied commanders.
Australians also joined Dutch-led missions
The relationship was not simply Dutch personnel using an Australian base.
Australian servicemen also became directly involved in operations organised by the Dutch/NEI intelligence sections.
One well-known example is Sergeant Leonard Siffleet.
Siffleet trained at Z Experimental Station in late 1942 while the Dutch section of ISD was preparing a mission to establish an intelligence and coastwatching station near Hollandia in Dutch New Guinea. He became the radio operator for that mission.
He was later captured by the Japanese and executed. The photograph of his execution became one of the most confronting images of the Pacific War.
His story demonstrates how thoroughly national boundaries could blur in the clandestine war. An Australian soldier could be trained at Cairns and assigned as radio operator to an operation developed by the Dutch section for service in Dutch New Guinea.
Cooperation continued after the Dutch takeover
The transfer of ZES to NEFIS did not end Australian use of the facility.
Peter Dunn’s research indicates that in 1945 the Dutch establishment at Cairns provided accommodation and transport to Australian SRD personnel attending courses in jungle food, jungle living and jungle tactics.
That is a useful reminder that “takeover” should not be interpreted as separation.
Dutch and Australian intelligence and special-operations organisations remained institutionally distinct, but they continued to exchange facilities, expertise and operational assistance when required.
The story of ZES was therefore not one of one nationality replacing another.
It was one of changing organisational control within an Allied intelligence system that remained highly interconnected.
A particularly Indonesian contribution
Perhaps the most overlooked part of the story is the role of Indonesians themselves.
The Netherlands East Indies intelligence organisations depended heavily upon men with local languages and knowledge of particular islands and communities.
Some were KNIL soldiers. Others came from the Royal Netherlands Navy, police, shipping or civilian backgrounds.
At Cairns they trained alongside Australians and Europeans for missions in which cultural knowledge could be as important as military skill.
The surviving evidence concerning Julius Tahija is a particularly striking example. An Ambonese KNIL officer was not merely receiving Australian or British instruction; he was helping instruct others.
This complicates any simple description of ZES as an Australian or even a Dutch wartime establishment.
It was a genuinely multinational environment involving Australians, British personnel, Dutch Europeans and Indonesians from across the Netherlands East Indies.
Part of a wider Queensland network
ZES was not the only Queensland location associated with both Dutch personnel and Allied clandestine operations. In Brisbane, Miegunyah House at Newstead had been used as a safe house for members of Z Special Unit connected with Operation Jaywick. In 1945 the house was commissioned by the Dutch Government, at a time when a number of Brisbane properties were being used by Dutch military and government personnel. The precise Dutch organisation that occupied Miegunyah has not yet been established.
The forgotten history of the House on the Hill
Today, the Z Experimental Station is generally remembered through the history of Australian special operations and Z Special Unit.
That history is important.
Operation Jaywick and the men who undertook Australia’s clandestine war against Japan deserve the place they hold in Australian military memory.
But the history of Fairview House was broader.
Dutch and Indonesian personnel were present from the station’s early days. Men from the NEI formed a substantial proportion of the operatives associated with ISD. Julius Tahija helped train agents there. Former Korps Insulinde commandos entered the Australian intelligence system. After the reorganisation of 1943, ZES became an important NEFIS III facility for training, communications, holding personnel and staging clandestine missions.
From a Queensland farmhouse overlooking Cairns, men were being prepared to return secretly to Java, New Guinea, the Moluccas and other parts of the occupied Netherlands East Indies.
The House on the Hill therefore deserves recognition as more than an Australian special-operations site.
It was also one of the places where the Netherlands rebuilt a clandestine operational capability after losing the Netherlands East Indies — and where Australian, Dutch and Indonesian personnel fought a secret war together.
Sources and further reading
Peter Dunn OAM, “Z Experimental Station Cairns (ZES) – The House on the Hill, Fairview Farm, Mooroobool, Cairns during WWII”, Australia @ War. Peter Dunn’s reconstruction is particularly useful for the establishment, personnel, facilities and changing wartime role of ZES.
Dr Jonathan (Jack) Ford, Allies in a Bind: Australia and the Netherlands East Indies in the Second World War, particularly his discussion of the establishment of NEFIS, Korps Insulinde personnel, training at Cairns and the operational experiences of NEFIS parties. Ford’s research draws extensively on Australian, Dutch, British and American archival material.
Dutch Australian Cultural Centre, “Dutch, Australian and Indonesian Agents: The NEI Section of Australia’s Secret War” — analysis of surviving ISD records showing the substantial Dutch and NEI personnel presence within the organisation and operations prepared at Cairns.
Dutch Australian Cultural Centre, “Julius Tahija was one of the few NEI men who received the Netherlands’ highest military order”.
Dutch Australian Cultural Centre, “WWII Netherlands Forces Intelligence Service operating from Australia”.
Loe de Jong, Het Koninkrijk der Nederlanden in de Tweede Wereldoorlog, Deel 11c, Nederlands-Indië III — discussion of the training of prospective clandestine agents at Cairns and shortcomings in early preparation for conditions in the Netherlands East Indies.
Australian War Memorial, glossary and collections relating to Z Experimental Station, Z Special Unit and the Services Reconnaissance Department.
Queensland Government, Anzac Square & Memorial Galleries, “Cairns ‘Z’ Experimental Station Commando Training School”.
Further archival research, particularly in National Archives of Australia Series A3269 and the Netherlands National Archives NEFIS collections, may reveal more detail concerning individual personnel trained at Cairns and the specific missions staged from ZES.
