The Australian portion of the Aitape-Wewak campaign took place in northern New Guinea between November 1944 and August 1945. Aitape had been occupied by the Japanese in 1942. Recaptured by an American landing on 22 April 1944, it was developed as a base area to support the continuing drive towards the Philippines. In order to free American troops for the Philippine operations, defence of the area was passed to Australian forces. Troops of the 3rd Base Sub Area and the 6th Division began progressively relieving the Americans from early October 1944.
Although their primary role was the defence of the base facilities at Aitape, Australian commanders opted to advance to the east of Aitape, towards Wewak, to destroy the remnants of the Japanese 18th Army. The 18th Army had sustained heavy losses as a result of Australian operations in the Salamaua hinterland, on the Huon Peninsula, and in the Finisterre Mountains. After preliminary patrolling by the 2/6th Cavalry (Commando) Regiment, the Australian advance by the brigades of the 6th Division began in December 1944. It had two axes - one along the coast towards the Japanese base at Wewak, and the other into the Torricelli Mountains, aimed at the area around Maprik used for the gardening and foraging upon which the Japanese force depended for its sustenance.
The resulting operations were characterised by prolonged small-scale patrolling, often in particularly arduous conditions. Assaults, when they occurred, were similarly small-scale - company attacks being the largest conducted in most instances. Constrained by supply difficulties, progress was slow but steady. But, on the coast was occupied on 16 March 1945, and Maprik was secured on 23 April. Wewak fell on 10 May. The remaining Japanese bastion in the area remained the Prince Alexander Mountains to the south of Wewak. Operations there were still continuing there when the war ended in August. Australian casualties in the campaign amounted to 442 killed and 1,141 wounded. Over 9,000 Japanese were killed and 269 became prisoners of war.
The Aitape-Wewak campaign is one of several of those fought in 1945 that has been subsequently branded an "unnecessary campaign". While there is no doubt that the Japanese troops, bypassed and isolated, were strategically irrelevant, there was also a political imperative that Australia should be seen to be clearing the Japanese from what was, at the time, Australian territory. Additionally, not knowing that the end of the war was just months away, Australia's military leadership was under pressure to reduce the size of the army, but also wished to have troops available for further operations towards Japan. To realise these goals, existing operational commitments needed to be reduced, which entailed clearing Japanese from areas such as Aitape-Wewak.