[1] Assigned to the 3rd Division, and consisting of personnel from the Australian Machine Gun Corps, the battalion had an authorised strength of 46 officers and 890 other ranks, and it consisted of four machine gun companies – the 9th, 10th, 11th and 23rd – which had previously existed as independent companies mainly assigned at brigade level.

[2] The establishment of machine gun battalions within the AIF was the final step in the evolution of the organisation of direct fire support during the war.

[1] At the end of the Gallipoli Campaign, the AIF was reorganised and expanded in preparation for its transfer to the Western Front,[3] and the machine gun sections within each infantry battalion had been consolidated into companies assigned at brigade level.

[4] The first three of battalion's constituent companies had been formed in Australia – in New South Wales, Victoria and Queensland – in February 1916 during a period when the AIF was being expanded in preparation for its transfer to the Western Front following the end of the disastrous Gallipoli Campaign.

[5] The battalion was equipped with a total of 64 Vickers medium machine guns – assigned at a scale of 16 per company – and took part in the final stages of the war, seeing action during the Allied defensive operations during the German spring offensive and then the Allied Hundred Days Offensive, which finally brought an end to the war.

Following the outbreak of World War II, four machine gun battalions were eventually raised as part of the Second Australian Imperial Force, each assigned at divisional level.

[9][11] The 5th Machine Gun Battalion was also re-raised and undertook garrison duties as part of Torres Strait Force.