Formed on 21 June 1942, it initially consisted of part-time Militia units and was under the command of Major General Basil Morris's New Guinea Force. Reinforced by veteran Second Australian Imperial Force units, Maroubra Force was instrumental in blunting the Japanese advance on Port Moresby, fighting it to a standstill in September, before elements of the 7th Division undertook a counter-attack in October and November 1942, which drove the Japanese back to their beachheads around Buna–Gona, which was the scene of heavy fighting between November 1942 and January 1943.