The Australian First Tactical Air Force was formed on 25 October 1944 by the Royal Australian Air Force (RAAF). Its purpose was to provide a mobile force of fighter and ground attack aircraft that could support Allied army and naval units fighting the Empire of Japan in the South West Pacific Area. One of several Allied tactical air forces formed during World War II, it evolved from the RAAF's No. 10 Operational Group, established a year earlier. Following action in the assaults on Aitape and Noemfoor, the group was renamed the First Tactical Air Force to better reflect its size and role. It was beset with morale and leadership issues in early 1945, but recovered to take part in the battles of Tarakan, North Borneo, and Balikpapan. Reaching its peak strength of over 25,000 personnel in July 1945, No. 1 TAF's squadrons operated such aircraft as the P-40 Kittyhawk, Supermarine Spitfire, Bristol Beaufighter, and B-24 Liberator. The formation remained active following the end of hostilities in the Pacific until it was disbanded on 24 July 1946.

The Battle of North Borneo took place during the Second World War between Allied and Japanese forces. Part of the wider Borneo campaign of the Pacific War, it was fought between 10 June and 15 August 1945 in North Borneo. The battle involved a series of amphibious landings by Australian forces on various points on the mainland around Brunei Bay and upon islands situated around the bay. Japanese opposition to the landings was sporadic initially, although as the campaign progressed a number of considerable clashes occurred and both sides suffered significant casualties, although major combat was largely restricted to Labuan and around Beaufort. On the mainland, while Allied conventional operations focused largely on the coastal areas around Brunei Bay, guerrilla forces consisting of Dayak tribesmen and small numbers of Allied personnel from the Services Reconnaissance Department fought an unconventional campaign in the interior. The Allies were successful in seizing control of the region. Nevertheless, many of the strategic gains that possession of North Borneo provided were ultimately negated by the sudden conclusion of the war in August 1945.