 On 7 June 1917 , the II Anzac Corps — along with two British corps — launched an operation in Flanders to eliminate a salient south of Ypres . The attack commenced with the detonation of a million pounds ( 454 @,@ 545 kg ) of explosives that had been placed underneath the Messines ridge , destroying the German trenches . The advance was virtually unopposed , and despite strong German counterattacks the next day , it succeeded . Australian casualties during the Battle of Messines included nearly 6 @,@ 800 men . I Anzac Corps then took part in the Third Battle of Ypres in Belgium as part of the campaign to capture the Gheluvelt Plateau , between September and November 1917 . Individual actions took place at Menin Road , Polygon Wood , Broodseinde , Poelcappelle and Passchendaele and over the course of eight weeks fighting the Australians suffered 38 @,@ 000 casualties . 
