In early 1942, elements of the Imperial Japanese Navy (IJN) proposed an invasion of mainland Australia. This proposal was opposed by the Imperial Japanese Army and Prime Minister Hideki Tojo, who regarded it as being unfeasible, given Australia's geography and the strength of the Allied defences. Instead, the Japanese military adopted a strategy of isolating mainland Australia from the United States by advancing through the South Pacific. This offensive was abandoned following the Battle of the Coral Sea and the Battle of Midway in May and June 1942, and all subsequent Japanese operations in the vicinity of Australia were undertaken to slow the advance of Allied forces.

Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. Australia is the largest country by area in Oceania and the world's sixth-largest country. Australia is the oldest, flattest, and driest inhabited continent, with the least fertile soils. It is a megadiverse country, and its size gives it a wide variety of landscapes and climates, with deserts in the centre, tropical rainforests in the north-east, tropical savannas in the north, and mountain ranges in the south-east.