From the 1920s Australia 's defence thinking was dominated by British Imperial defence policy , which was embodied by the " Singapore strategy " . This strategy involved the construction and defence of a major naval base at Singapore from which a large British fleet would respond to Japanese aggression in the region . To this end , a high proportion of Australian forces in Asia were concentrated in Malaya during 1940 and 1941 as the threat from Japan increased . However , as a result of the emphasis on co @-@ operation with Britain , relatively few Australian military units had been retained in Australia and the Asia @-@ Pacific region . Measures were taken to improve Australia 's defences as war with Japan loomed in 1941 , but these proved inadequate . In December 1941 , the Australian Army in the Pacific comprised the 8th Division , most of which was stationed in Malaya , and eight partially trained and equipped divisions in Australia . The RAAF was equipped with 373 aircraft , most of which were obsolete trainers , and the RAN had three cruisers and two destroyers in Australian waters .