The 3rd Australian Corps Guerilla Warfare Group (3 Aust Corps Guerilla Warfare Group) had its beginnings as the Special Duties Unit which was formed at Broome straight after the Japanese attack on Broome on 3 March 1942. The Special Duties Unit was formed to deal with the luggers in Broome and they repaired the best ones to sail south while burning the others. It was a naval led mission which did their job and left. Some of the luggers that headed south were wrecked in a storm and the others stopped off at Geraldton.

A group from 13 Field Company was also sent north to install demolition charges in the Broome area and they became a detachment of 7 Army Troops Company in June and were withdrawn in August. One of the men in the 13 Field Company was Sapper Maxwell John Clarke (W19277). In his papers Max Clarke describes demolition charges placed on the jetty, the wireless station and nearby weather bureau, the post office, buildings at the airfield, the power station, the meat works, the artesian bores and the bomb dump. Three drums of petrol and one drum of diesel were placed along the jetty at Broome at intervals (1/3, 1/2, and at the end) for the purpose of firing the jetty. At a distance of 1/3 from the shore there was also a four main necklace charge with a five minute fuse placed around the piles plus several small subsidiary shattering charges along the top of the jetty. If the need for demolition arose, the petrol and diesel would be spilled along the jetty and the fuse to the four main necklace charges would be lit before placing a match to the spilled fuel. The 30 second fuses of the shattering charges would be set off by the flames from the spreading fire.

Major George Deane Mitchell (NX156027) DSC MC came over to Western Australia as a Liaison Officer to HQ 3 Aust Corps in April 1942, travelling with William "Bill" Grayden (WX8868) who was going on leave from 2/16 Aust Inf Bn. Mitchell's specific brief was to form an independent unit in the north west and Grayden joined him, driving up to Broome recruiting men to form the unit along the way. By June 1942, the 2/16 Aust Inf Bn had got wind of Grayden’s unofficial detachment and he was ordered to rejoin his unit. Mitchell gathered men where he found them, including the remnants of the Special Duties Unit at Geraldton (and one of the luggers).

By July 1942, Mitchell was able to put some structure into the Special Independent Company which was formed in Perth. Most of the men were part timers with a core of FTD (full time duty) men who travelled around training the station men. Sections were established at:-

Halls Creek
Roy Hill
Glen Florrie
Meekatharra
Mooloo
Yaringa

Their role was to patrol their local areas and look for evidence of Japanese landing parties and to prepare for Guerilla warfare. Major Mitchell was attached to the Special Independent Company on 16 August 1942. Their Company Headquarters moved around to a number of locations including:-

Broome
Carnarvon
Geraldton
Mt. Lawley
Chidlows
Point Walter

The Special Independent Company became the nucleus of the 3rd Australian Corps Guerilla Warfare Group by October 1942. They carried out many long range patrols including a 500kms patrol through the Kimberley in 1942, and one to Munja Station in 1943. They comprised a group of 60 plus handpicked men with outback bush survival skills. They were mainly young shearers or station hands who had lived in the outback of Western Australia. They knew how to live off the land and many had worked with Aboriginal stockmen on remote cattle stations. Some of the men who joined the 3rd Australian Corps Guerilla Warfare Group also came from the proposed reinforcements for the 2/4th Machine Gun Regiment who had originally been destined to join their unit in Singapore. Unfortunately the 2/4th Machine Gun Regiment was captured by the Japanese in Singapore in February 1942.

In November and December 1942, forty men from the 3rd Australian Corps Guerilla Warfare Group moved inside the Leopold Ranges and trekked 300 miles. Up to 12 Munja native guides were used as the only three white men who knew the area were either sick or unavailable.

Major Mitchell was allotted as the Commanding Officer of the 3rd Australian Corps Guerilla Warfare Group on 24 October 1942. Mitchell had served during WWI and saw service at Gallipoli. He was awarded his DCM for conspicuous gallantry and devotion to duty - "He handled his machine gun with great skill throughout the operations and was largely responsible for driving off a strong enemy counter attack."

On 29 September 1942, Cyril Longmore, a war correspondent with the West Australian submitted a proposal to Mr Forde, the Minister for the Army, to establish a Native Auxiliary Corps. The Minister for the Army referred the submission to the G.O.C., 3rd Australian Corps for investigation. His response was unfavourable and was supported by the Commissioner of Native Affairs. Forde reported back to Prime Minister John Curtin on 12 December 1942:-

"Considering all the circumstances, it is felt that it would be unsound to arm any of the natives in the Kimberley district and, however attractive the scheme may appear in theory, I suggest that it would not be advisable to proceed with it."

Major Mitchell submitted a report on 6 March 1943 on Longmore's proposal to establish a "Native Auxiliary Corps". In his report Major Mitchell commented that had the 12 Munja natives who went on the trek inside the Leopold Ranges had training, they would have been ideal for any fighting operations. Captain Longmore had trained a native platoon at Liveringa and the results exceeded all expectations. They developed weapons skills and steadiness under fire and were invaluable during night time operations. The Native Platoon at Liveringa washed themselves and their clothes religiously. They were never late for parades. Their weapon handling was better than white recruits of similar training. Their steadiness in a trench showered with bullets and surrounded by dynamite blasts was faultless. Their throwing of live grenades was better than that of our trained men. Scouting and night work came naturally to them.

Mitchell went on to state in his report that:-

"The only natives worth training by reason of physique, warlike nature and original independence are those in the triangle NOONKANBAH-DRYSDALE-MUNJA, but there are plenty to work on there, only a few being engaged on station work."

After receiving the bad news on 16 April 1943 on the rejection of his proposal, Longmore wrote again to Prime Minister John Curtin on 19 April 1943 refuting some of the claims in the letter of 16 April.

Prime Minister John Curtin referred Mitchell's report to Forde on 22 June 1943 and asked for it to be passed on to General Blamey for comment. Forde reported back to Prime Minister John Curtin on 5 August 1943, stating that Mitchell's report had been sent to General Blamey and that the Commander-in-Chief considered "that in light of the present strategical situation, no useful purpose would be served by raising a Unit of the nature mentioned, at this time."

In 1943 the 3rd Australian Corps Guerilla Warfare Group investigated a Skysign made of black stones on a white saltpan. It was thought that it may have had some connection with Japanese activities in the area.