 An alternative policy was put forward in 1923 by the Australian Labor Party , which was in opposition for all but two years of the 1920s and 1930s . It called for Australia 's first line of defence to be a powerful air arm , supported by a well @-@ equipped Australian Army that could be rapidly expanded to meet an invasion threat . This , in turn , required a strong munitions industry . Labor politicians cited critics like Rear Admiral William Freeland Fullam , who drew attention to the vulnerability of warships to aircraft , naval mines and submarines . The Labor Party 's Albert Green noted in 1923 that when a battleship of the day cost £ 7 @,@ 000 @,@ 000 while an aircraft cost £ 2 @,@ 500 , there was a genuine cause for concern as to whether the battleship was a better investment than hundreds of aircraft , if the aircraft could sink battleships . The Labor Party 's policy became indistinguishable from the Army 's position . 
