In 1943 Serong served as General Staff Officer 2 with the combined 6th and 7th Divisions on the Atherton Tableland in Far North Queensland, where they were resting and retraining prior to conducting further operations. In early 1944 he instructed on the staff course at Cabarlah. That August, he moved to Aitape to prepare for the deployment of the 6th Division. He was later attached to American forces for the landing on Morotai Island in the Netherlands East Indies in mid-September 1944. In the last few weeks of the war, Serong was mentioned in despatches for his actions fighting the Japanese at Wewak, whilst serving with the infantry in the 35th Battalion. During an incident on 21 July 1945, he commanded a force of three platoons and native police on a patrol to destroy a Japanese ammunition dump. Although serving more time in training roles than in combat, during the war Serong had made important contacts with whom he would later work in future postings, including Colonel Reg Pollard, who went on to become Chief of the General Staff (CGS), and Colonel Charles Spry, later the Director of Military Intelligence and the Director General of the Australian Security Intelligence Organisation (ASIO).