In May 1943, No. 4 Squadron was re-equipped with CAC Boomerang fighter aircraft, to be operated in a tactical reconnaissance role. Operating with these new aircraft and also some Wirraways it had retained, the squadron supported the Australian 7th and 9th Divisions during the Huon Peninsula campaign. It also operated six Piper Cubs as liaison aircraft during these campaigns. The squadron continued to support Australian, US Army and US Marine Corps units in New Guinea and New Britain until March 1945 when it deployed to Morotai and then to the island of Labuan to support Australian ground forces in the Borneo campaign. It supported the 9th Division's campaign in North Borneo and the 7th Division's landing at Balikpapan. Casualties during the war amounted to 37 personnel killed.