The 'Brisbane Line' was the Australian defence proposal purported to have been drafted during World War II to withdraw Allied forces from the northern portion of the continent should the Japanese invade the country.

Although a preliminary scheme of February 1942 to give primary importance to the defence in the essential industrial areas, between Brisbane and Melbourne in the south-eastern part of the country, should the Japanese launch an invasion, this had been rejected by the Labour prime minister, John Curtin, and the Australian war cabinet. Lacking any real understanding of this proposal and other responses to the possible Japanese invasion, the Labour party’s Eddie Ward, who was the minister for labour and national service, to claim that the previous government (a United Australia Party/Country Party coalition under the leaderships first of Robert Menzies and then of Arthur Fadden) had planned to abandon much of northern Australia to the Japanese.

Ward continued to moot this idea in the period between late 1942 and early 1943, and the idea that it was an real defensive strategy gained support after General Douglas MacArthur mentioned it in March 1943 during a press conference in which he also first mentioned a 'Brisbane Line'. Ward initially offered no evidence to support his claims, but later claimed that the relevant records had been removed from the official files. A royal commission later came to the conclusion that there had never been any such documents, and that government under Menzies and Fadden had not approved plans of the type alleged by Ward. Even so, the controversy aided the the political ambitions of the Labour Party, which secured victory in the 1943 federal election.