With Japan's entry into the war in December 1941, the Malayan Campaign and Fall of Singapore, the strategic situation worsened significantly. 7 Fld Coy was called out for full-time service within Australia in May 1942. Later, 7 Fld Coy was re-gazetted as an AIF unit. The unit served in Papua New Guinea and fought against the Japanese along the Kokoda Track and on Bougainville until the end of the war.