During 1943 and 1944 he saw active service in Papua New Guinea on three separate occasions, serving as an Intelligence Officer with both HQ New Guinea Force and HQ 3rd Division 2AIF during the war against the Japanese 51st Division at the Battle of Wau and the Salamaua–Lae campaign. His duty was the gathering of intelligence from outlying spotter posts behind enemy lines, and carrying orders and intelligence back and forth along the Black Cat Track and the Buisaval Track between front-line troops and HQ. It also included a 5-week period in July 1943 when he was promoted in the field to Major and traversed the Bitoi River Track alone to act as Senior Liaison Officer with the United States Army's 41st Division 162nd Regiment at Nassau Bay.