Until the 1970s , Australia 's military strategy centred on the concept of Forward Defence , in which the role of Australian military and naval forces were to co @-@ operate with Allied forces to counter threats in Australia 's region . Following the adoption of the Guam Doctrine by the United States in 1969 , and the British withdrawal ' east of Suez ' in the early 1970s , Australia developed a defence policy emphasising self @-@ reliance and the defence of the Australian continent . Known as the Defence of Australia Policy , it focused Australian defence planning on protecting the nation 's northern maritime approaches ( the ' air @-@ sea gap ' ) against possible attack .