 Complete the following phrase:  During the interwar years, the machine gun battalions disappeared from the Australian Armys order of battle, largely due to cost-cutting measures. The idea would be revived in the Australian Army in the late 1930s due to concerns about war breaking out in Europe, and subsequently four machine gun battalions were raised as part of the Second Australian Imperial Force  the a href21st20Machine20Gun20Battalion2028Australia2921sta, a href22nd20Machine20Gun20Battalion2028Australia2922nda, a href23rd20Machine20Gun20Battalion2028Australia2923rda and a href24th20Machine20Gun20Battalion2028Australia2924tha  for service during World War II, while several others would be formed within the Militia, either by converting motorised Light Horse units, or by raising new battalions. The 2nd AIF battalions served in the Middle East, Greece, Syria, Malaya, Singapore, New Guinea and Borneo, while the Militia units were used primarily in a garrison role in Australia and New Guinea, although they saw some action against Japanese forces around 