In early August 1915, Hastings was heavily involved in the Allied offensive that attempted to break the deadlock of the Gallipoli campaign through the simultaneous push for the heights above Anzac and lodgement of a new British force at Suvla Bay. After dark on 6 August the New Zealand Mounted Rifles Brigade commenced its task of clearing the Ottomans from the lower slopes of the Sari Bair range beginning with the Old No. 3 Outpost. During this attack Hastings led two platoons of Maori Pioneers in destroying barbed-wire entanglements in the Sazli Beit Dere before the Wellington Mounted Rifle Regiment stormed Destroyer Hill and Table Top. Hastings' party assisted the Auckland Mounted Rifles Regiment by attacking trenches in the Old No. 3 Outpost and took some prisoners on the northern end of the position.