The First Australian Army was a field army of the Australian Army, during World War II. The formation's headquarters was raised in April 1942 from the existing 1st Australian Corps headquarters, assuming command of all Allied troops in Queensland. Initially, the formation was assigned a defensive role in anticipation of a possible Japanese invasion; however, this threat subsided and eventually the army was deployed to Lae, in New Guinea, in late 1944, where it co-ordinated Australian offensives around Aitape, in New Guinea, on New Britain and Bougainville, and around Madang. The formation was disbanded in February 1946, when it was redesignated as the 8th Military District.

I Corps was an Australian Army corps, one of three that were raised by the Army during World War II. It was the main Australian operational corps for much of the war. Various Australian and other Allied divisions came under its control at different times. In 1940–1942, the corps was based in the Mediterranean and Middle Eastern theatres, and controlled forces in action against the Germans, Italians and later the Vichy French in North Africa, Greece and Syria–Lebanon.