 On 9 March 1944, Dechaineux was given command of the heavy cruiser HMAS "Australia", the flagship of both the RAN and Task Force 74, under the overall force commander Commodore John Collins.The "Australia" supported Allied landings at Hollandia in Dutch New Guinea and on the islands of Biak, Noemfoor and Morotai.On 21 October 1944, HMAS "Australia" was supporting the landings in Leyte Gulf.