 At the start of the Gallipoli Campaign , the AIF had four infantry brigades with the first three making up the 1st Division . The 4th Brigade was joined with the sole New Zealand infantry brigade to form the New Zealand and Australian Division . The 2nd Division had been formed in Egypt in 1915 and was sent to Gallipoli in August to reinforce the 1st Division , doing so without its artillery and having only partially completed its training . After Gallipoli , the infantry underwent a major expansion . The 3rd Division was formed in Australia and sent to France . The New Zealand and Australian Division was broken up with the New Zealand elements forming the New Zealand Division , while the original Australian infantry brigades ( 1st to 4th ) were split in half to create 16 new battalions to form another four brigades . These new brigades ( 12th to 15th ) were used to form the 4th and 5th Divisions . This ensured the battalions of the two new divisions had a core of experienced soldiers . The 6th Division commenced forming in England in February 1917 , but was never deployed to France and was broken up in September of that year to provide reinforcements to the other five divisions . 
