Borneo campaign (1945)

Op semut 2.jpg

Operation SEMUT was a series of reconnaissance operations carried out by Australia's Z Special Unit during World War II. This operation was the part of the Borneo Campaign at Sarawak, northwestern Borneo. Another closely related operation codenamed AGAS was carried out in North Borneo (present day Sabah). Both operations combined and relayed their intelligence through the STALLION project to Australian forces and carried out guerilla warfares against the Japanese in the region with the full support of the natives.

The idea of operating deep behind the Japanese line and organising an indigenous resistance against the Japanese operations in Sarawak was conceived as early as December 1941. Second Lieutenant P. M. Synge of the British Intelligence Corps based in Oxford, England, proposed that "a force of 500 men or more if necessary, skilled in forest-craft, could be raised from the Long Houses of the Baram, Tinfar [Tinjar] and Niah rivers and organised into an effective guerilla force'. Lieutenant Synge then submitted a proposal of the operations in February 1942 but it was not approved because was not feasible at that time. In July 1942, Tom Harrisson, who was an Oxford Sarawak Expedition leader in 1932, drew another similar proposal that put an emphasis on operations against Seria oilfields in Brunei rather than Miri oilfields in Sarawak. Meanwhile, Captain D. L. Leach proposed the need to contact ex-Brooke officials, natives, and Chinese who are still loyal to the Allied forces and to establish three main bases at Baram river, Rejang basin, and Rejang upriver.


The operation was finally carried out in 1945 by Australian Services Reconnaissance Department (SRD) with two main objectives: to gather intelligence and to train the indigenous people in launching guerilla warfare against the Japanese. The operation was under the overall command of Major G. S. Carter, and was divided into three distinct parties: SEMUT 1 under the command of Major Tom Harrisson, SEMUT 2 under the command of Major G. S. Carter himself, and SEMUT 3 headed by Captain W. L. P. Sochon. SEMUT 1 would operate at the Trusan valley, SEMUT 2 at Baram valley, and SEMUT 3 at the entire Rajang valley. Tom Harrisson and his SEMUT 1 team parachuted at Bario, Kelabit highlands in March 1945, however, upon the completion of small airstrip in Bario by using native labour, he shifted his base to Belawit in the Bawang valley in Dutch Borneo. SEMUT 2 team also parachuted into Bario in mid-April with the full support from the Kelabit people, the moved to the Baram valley and established a base at Long Akah. Sochon and his team then moved out from SEMUT 2 team and lead the SEMUT 3 team to Belaga at Upper Rajang, with full support from the Kayan and Iban there. All the intelligence from these operations were relayed to Blamey's Advanced Land Headquarters at Morotai in the Halmahera. Four days before the launch of the Operation Oboe Six (Battle of North Borneo), SEMUT 2 team captured a Japanese wireless station at Long Lama. On 9 June 1945, on the eve of the Australian landings at Labuan island, SEMUT 1 team attacked a small Japanese garrison at Brunei Bay.[3]


On 26 April 1945, a plan named STALLION was implemented to collect intelligence from Operation SEMUT and AGAS regarding the Japanese positions at Burnei Bay.[3]

At Sarawak on the 2nd August 1945, Lieutenant Frank Oldham paddled up Balui River from Balaga with a patrol, then to Long Nawang to prepare for a planned re-occupation by Allies and investigate Japanese atrocities.[citation needed]

At Sarawak on the 13 to 23 August 1945, SEMUT IVB. sailed out of Labuan via HMAS Tigersnake and moored at Mukah. Party leader; Lieutenant Rowan Waddy and Lieutenant Ron Hoey, paddling Hoehn folboats (collapsible canoes) journeyed along the Mukah River to engage, with the help of local natives, any remaining hostile Japanese groups. On the way they were threatened by a crocodile about the length of the folboat.


In June 1945, SEMUT 1 had armed units spread thinly, covering the entire northern Sarawak and had an outpost at Pensiangan and as far as Tenom in North Borneo. They also established several bases at Dutch Borneo. Based solely upon the native intelligence, Australian were able to grasp information regarding Japanese positions and movements in Brunei and northern Sarawak, and information regarding POW (prisoner of war) and civilian internees in the region. About 600 natives were trained and supplied with arms and ammunition. SEMUT 1 also carried out operations to deny food and labour supply for the Japanese.

SEMUT 2 also expanded their operation area to Bintulu and Upper Rajang at central Sarawak and trained 350 native guerilla force. SEMUT 3 expaneded their operation area to Kapit in central Sarawak. In 1959, Tom Harrison claimed that "The unit had inflicted some 1,700 casualties on the Japs at the cost of some 112 white lives", and credited SEMUT 1 with over 1,000 out of 1,700 Japanese killings.

The information relayed by the natives, however, were sometimes erroneous, where the progress of Australian imperial force (AIF) was hindered by incorrect information regarding Japanese strength and dispositions. Concerns has been raised regarding the interrogators where they did not assess the reliability of the information before passing them to the headquarters. Besides, the natives were not able to differentiate facts and opinions from rumours circulating the region and subsequently passed incorrect information to the Australian forces. Due to Japanese counter-intelligence efforts, European officials cannot be inserted into the SEMUT and AGAS intelligence network to supervise the intelligence gathering.


Roland Griffths-Marsh as interviewed in A Secret War

Roland Griffths-Marsh as interviewed in A Secret War

Griffiths-Marsh was born in Penang, then part of the British Straits Settlements, on 22 April 1923 and grew up in Hai PhongIndochina. On 29 February 1940, at the age of sixteen, he enlisted with the Second Australian Imperial Force, taking his older brother's name and date of birth to ensure entry.

Roland Griffiths-Marsh.jpg

Griffiths-Marsh served in the 2/8th Battalion in North Africa and New Guinea, before being recruited to Z Special Unit, a specialist reconnaissance and sabotage unit that operated behind Japanese lines in South-East Asia. He served in the Semut I operation in North Borneo, and was parachuted behind enemy lines to conduct guerrilla warfare with the assistance of local fighters in early June 1945. He was awarded the Military Medal for his service with Z Special Unit, the award was gazetted on 6 March 1947, dated 2 November 1945. The original recommendation for the award states:

...he quickly formed a small guerilla [sic] force to harass the Japs escaping through the area. He showed a quick grasp of native mentality and a real ability to lead native troops... In this area he killed 34 Japanese and captured 4. In August he took charge of blocking the track from SAPONG estate west to MAHAMAN in conjunction with 9th Aust Div which he carried out with marked success, killing a further 4 Japs and capturing valuable intelligence reports and maps. During these experiences, Griffiths lived wholly on native food and covered large distances on foot through dangerous country. At all times his bearing and conduct were of a very high standard.

Griffiths-Marsh wrote about his wartime experiences in his 1990 book Sixpenny Soldier. That same year the book was awarded both The Nettie Palmer Prize for Non-fiction (one of the Victorian Premier's Literary Awards), and the Colin Roderick Award, awarded annually for "the best book published in Australia which deals with any aspect of Australian life" along with the H.T. Priestley Memorial Medal. This book was republished under the title I was Only Sixteen in 1995.

Papers by Griffiths-Marsh about the training of his native guerrilla force and service in North Borneo are held at the Australian War Memorial.

Griffith-Marsh died on 29 December 2012 aged 89.


Operation Semut Links

Journal of the Australian War Memorial - Issue 37

Prelude to invasion: covert operations before the re-occupation of Northwest Borneo, 1944-45

A Matter of Trust: Dayaks & Z Special Unit Operatives in Borneo 1945 Exhibition