Wewak is a town on the northern coast of New Guinea, which in 1942 was the administrative centre for the Sepik District. In December of that year it was occupied by the Japanese and subsequently developed as their largest base in New Guinea, with both a substantial airfield and small-scale port facilities. Following its defeat at the hands of Australian and American troops in the campaigns of 1943-44, the Japanese XVIII Army had retreated to the Wewak area from south-eastern New Guinea. It was these troops that the 6th Australian Division sought to destroy in the Aitape-Wewak campaign in 1945.
The Australian advance along the coast from Aitape closed on Wewak in early May 1945. By this time the Japanese strength there was estimated as being up to 1,000 personnel from the headquarters of the 51st Division, the 66th and 102nd Regiments, and the 25th Airfield Battalion. With intelligence indicating that the Japanese were abandoning Wewak to withdraw into the Prince Alexander Mountains, it was attacked by the 2/4th Battalion on the morning of 10 May. After an artillery barrage of 2,700 rounds, B and D Companies, each supported by a troop of Matilda tanks from the 2/4th Armoured Regiment advanced onto Wewak point just after 6 am. The battle proceeded bunker by bunker throughout the day, A and C Companies taking over the attack once B and D had secured their objectives. Many of the Japanese strongpoints were located in deep caves and had to be dealt with by the tanks, or with flamethrowers, and some only fell at bayonet point. By nightfall enemy resistance in Wewak had ceased, although numerous small parties of Japanese troops sought to escape through the Australian positions after dark. Mopping-up continued the next day and Wewak was declared secure by midday. Wewak airfield was captured without opposition on 12 May. Five Australians and up to 200 Japanese were killed in the fighting for Wewak.