III Corps was an Australian Army unit during World War II. It was responsible for the defence of Western Australia in 1942–1944. The corps was formed in April 1942 from Western Command, which had been established in October 1939. Throughout the war, the formation's size expanded and contracted as available manpower, and the strategic situation, dictated. At its height, the corps consisted of two infantry divisions and one armoured division, which were deployed to defend against a Japanese invasion threat, which ultimately never eventuated. The corps ceased to exist in June 1944 when it was converted back into Western Command, which remained until the end of the war in 1945. History The corps was raised from the previously existing headquarters Western Command, which had been formed in October 1939 at Swan Barracks, in Perth, Western Australia from the 5th Military District as part of initial war preparations following the declaration of war in Europe. In the early stages of the command's existence, there were few troops to spare, as most of the defensive forces from the Militia were deployed along the eastern coast of Australia. The founding unit of Western Command was a West Australian-formed Militia unit, the 13th Infantry Brigade. This supported by the 10th Light Horse Regiment and the 25th Light Horse (Machine Gun) Regiment. Two garrison battalions – the 5th and 10th – also provided defensive support around Fremantle. A third garrison battalion, the 19th, was also raised in Western Australia around this time for close defence, and they eventually formed the 5th Garrison Brigade; internment camp security was provided by 'M' Garrison Company. In mid-1942, as elements of the Second Australian Imperial Force returned from the Middle East, and fears of Japanese surface attacks against the Australian mainland increased, the Australian government decided to reinforce Western Australia in the wake of the Western Australian emergency of March 1942. The 6th Infantry Brigade arrived in April 1942, and was followed by the 4th Division, a Militia division raised in Victoria, and the 2nd Infantry Brigade. The same month, III Corps headquarters was established at Mount Lawley, Western Australia. Lieutenant General Gordon Bennett, who had previously commanded the 8th Division in Malaya and on Singapore, was appointed corps commander, replacing Major General Eric Plant who had commanded Western Command. Shortly after its establishment, III Corps was placed under the command of the South West Pacific Area. In August