Australians played a central role in the New Guinea campaign during 1942 and 1943 . After an attempt to land troops at Port Moresby was defeated in the Battle of the Coral Sea , the Japanese attempted to capture the strategically important town by advancing overland across the Owen Stanley Ranges and Milne Bay . Australian Army units defeated these offensives in the Kokoda Track campaign and Battle of Milne Bay with the support of the RAAF and USAAF . Australian and US Army units subsequently assaulted and captured the Japanese bases on the north coast of Papua in the hard @-@ fought Battle of Buna @-@ Gona . The Australian Army also defeated a Japanese attempt to capture the town of Wau in January 1943 and went onto the offensive in the Salamaua @-@ Lae campaign in April . In late 1943 , the 7th and 9th Divisions played an important role in Operation Cartwheel , when they landed to the east and west of Lae and secured the Huon Peninsula during the Huon Peninsula campaign and Finisterre Range campaign .