 The Australian and New Zealand Army Corps ( ANZAC ) was formed from the AIF and NZEF in preparation for the Gallipoli Campaign in 1915 and was commanded by Birdwood . Initially the corps consisted of the 1st Australian Division , the New Zealand and Australian Division , and two mounted brigades — the Australian 1st Light Horse Brigade and the New Zealand Mounted Rifles Brigade — although when first deployed to Gallipoli in April , it did so without its mounted formations , as the terrain was considered unsuitable . However , in May , both brigades were dismounted and deployed along with the 2nd and 3rd Light Horse Brigades as reinforcements . Later , as the campaign continued the corps was reinforced further by the 2nd Australian Division , which began arriving from August 1915 . In February 1916 , it was reorganised into I and II ANZAC Corps in Egypt following the evacuation from Gallipoli and the subsequent expansion of the AIF . 
