1942, the 2nd Division, a New South Wales Militia unit, joined III Corps. It was headquartered at Guildford, while the 4th Division was headquartered at Moora. A large-scale anti invasion exercise was undertaken by the 4th Division around Geraldton in October 1942, during which time the 8th Infantry Brigade assumed the role of an attacking Japanese force, while the 2nd, 6th and 13th Infantry Brigades assumed defensive roles. Throughout late 1942, the corps' infantry divisions traded locations, with the 2nd Division moving into positions around Geraldton and Mingenew, and the 4th Division establishing itself in the Dandaragan–Gingin–Bellevue area, eventually establishing its headquarters around Guildford in December 1942. The corps was expanded in October and November 1942, with the arrival of the first elements of the 1st Armoured Division, consisting of two brigades. These elements were the 3rd Motor Brigade, which occupied Mullewa; they were joined by the divisional headquarters in February 1943, and then the 1st Armoured Brigade in March. The remainder of the division arrived in April 1943, and eventually, the division would be based around Geraldton. By this time, though, the threat of invasion had diminished and after this the corps was progressively drawn down, with the 6th and 13th Infantry Brigades being transferred out in January and February 1943. According to the Army History Unit: The main function of the corps then became the preparation of smaller units for active service in New Guinea and elsewhere in the Pacific. A succession of units then passed rapidly through it, as they were transferred closer to the fighting to the north of Australia. The 4th Division's headquarters moved to Townsville, in April 1943, at which time the 2nd Infantry Brigade was transferred to the 2nd Division, although it later departed for the Northern Territory in August 1943. The 1st Armoured Division's headquarters was rolled up in September 1943, and the 3rd Motor Brigade being transferred to the 2nd Division, while the 1st Armoured became a direct command unit of the corps headquarters. The same month, the 8th Brigade was transferred to the 5th Division and began moving east. By the end of the year, corps headquarters moved to Swan Barracks, in Perth, from Mount Lawley. Concerns of a Japanese attack in March 1944 resulted in the corps being placed on notice to respond at short notice. However, the threat passed and further reductions took place throughout the early part