 Because of the restrictions that the Defence Act ( 1903 ) placed upon deploying units of the Citizens Force overseas , following the outbreak of World War I , the Australian government decided to raise an all volunteer force for overseas service . This force was known as the Australian Imperial Force ( AIF ) . Initially , the AIF was to consist of only one infantry division , but following the despatch of the 1st Division in late 1914 further units were raised and these were eventually organised to form the 2nd Division . As part of the 2nd Division , the 27th Battalion was formed on 16 March 1915 at Ascot Park Camp , Adelaide , from recruits drawn mainly from South Australia , who had originally been allocated to the 24th Battalion . After a period of basic training , the battalion embarked for the Middle East on the troopship HMAT A2 Geelong on 31 May 1915 , arriving there on 6 July . 
