Formation The 31st/51st Battalion was formed on 12 April 1943 at Yatlee, near
Cairns,
Queensland, Upon establishment, the battalion adopted the territorial title of the "Kennedy/Far North Queensland Regiment", in order to perpetuate the designations of its two predecessor units. Although the battalion officially adopted the brown and yellow rectangular
Unit Colour Patch of the 31st Battalion, members of the new battalion that had previously served with the 51st were authorised to wear its brown over light blue circular colour patch. Reinforcements to the unit were allocated the colour patch based upon the territorial area from which they had been recruited. In an attempt to rectify this situation, the Australian government made the decision to release Militia personnel who had previously been employed in "essential industries" back into the civilian workforce. As a result of this, both the 31st and 51st Battalions, which had large numbers of personnel drawn from the agricultural sector, were well below their authorised establishments, and so it was decided that they would be merged to form a complete battalion. In June–July 1943, under the command of Lieutenant Colonel Geoffrey Brock, the battalion was deployed to
Merauke, in
Dutch New Guinea when a small patrol of nine men on board the
Rosemary, a small diesel trawler, surprised a Japanese patrol consisting of two barges. In the fighting that followed, between 20 and 30 Japanese were killed for the loss of one Australian killed and five wounded. The second action came on 30 January 1944 when a waterborne force of about 200 Japanese was contacted and engaged by a 14-man detachment at an outpost near the start of the Eilanden River, about from Merauke. Anchoring about from the outpost, the Japanese were engaged with fire from
Bren light machine-guns, small arms and anti-tank rifles. Initially taken by surprise, the Japanese lost about men 60 killed before withdrawing about out to sea and engaging the outpost with heavy machine-guns and mortars. Nevertheless, only three Australians were slightly injured as a result of the contact, receiving burns to their hands from their overheated Bren guns. On 24 July 1944, the battalion was gazetted as an
Australian Imperial Force unit, meaning that it could be sent outside of the bounds imposed upon Militia units as set out in the
Defence Act (1903). Shortly afterwards, they received orders that they would be withdrawn back to Australia in preparation for employment in combat elsewhere in the Pacific theatre. On 8 August the battalion embarked to return to Australia. The battalion then began an offensive
campaign which saw them involved in heavy combat with the Japanese. They were committed to the fighting in three periods. The first, between December 1944 and February 1945, saw the battalion take
Tsimba Ridge, cross the Genga River and capture Downs Ridge. Conceived as a
company-level effort to outflank the significant Japanese defences that were holding up the advance from Ratsua, the operation was plagued by poor planning, inadequate resources, intelligence failures and strategic and tactical errors at all levels. After landing at the wrong beach on 8 June, and finding themselves caught in a tight box of Japanese defensive positions, the 190 men from 'A' and 'C' Companies, under Captain Henry Downs, were unable to advance inland. One of the landing craft ran aground and supplies began to dwindle. In an effort to link up with the beleaguered company, 'D' Company, which was holding the line along the Ratsua front, attempted to break through the Japanese lines. Although some patrols were able to penetrate to within of Porton, they were unable to get any closer. Eventually the order to withdraw was given from 11th Brigade headquarters. During the subsequent evacuation, two more landing craft ran aground and although one managed to float free, the other remained stuck hard on a reef. Following the failure of the landing at Porton Plantation, the planned Australian advance into the Bonis Peninsula was called off, and the Australians focused their main effort on Bougainville towards the capture of Buin in the south. The effort in the north was reduced to that of a holding action as further resources were transferred out of the sector. Nevertheless, the 31st/51st Battalion continued to undertake patrols along the Ratsua front, during which they suffered further casualties, until they were withdrawn from combat operations on 28 June.
Disbandment Following the cessation of hostilities on 15 August 1945, the battalion undertook garrison duties on
Nauru and
Ocean Island. As personnel were discharged or transferred to other units for further service, the battalion's numbers declined until eventually, on 4 July 1946, the battalion was disbanded. A further re-organisation saw the units split again in 1965 and re-raised as battalion-level formations under their old numerical designations. They have remained separate since then. ==Battle honours==