In late 1944, the battalion began deploying company-sized elements in support of combat operations on Bougainville, New Britain and on mainland New Guinea.

This unit had first seen combat in 1942,[1] and as a result of its successes in November 1943 the Australian Army authorised the establishment of another battalion, recruited from New Guinea.

[3] Although it was raised late in the war the battalion would ultimately serve in a number of the Allied campaigns in New Guinea, including during the offensives on New Britain and Bougainville.

[3] In November 1944, the PIB along with the 1st and 2nd New Guinea Infantry Battalions were amalgamated to form the Pacific Islands Regiment.

[8] In late January 1945, a long range patrol was moved by sea to Motupena Point, from where they attacked a Japanese outpost.

On 19 January 1945, a 1 NGIB patrol attacked a platoon-sized Japanese force around Bosman, killing 22 and capturing a large quantity small arms and a machine gun.

Over the period of two months, patrol operations by Australians and New Guineans resulted in 91 Japanese being killed.

[13] In March 1945, the company was transferred to Jacquinot Bay on New Britain, travelling from Madang to join the rest of the battalion.

[3] Battalion headquarters main arrived on New Britain in June 1945 and established itself around the Tol Plantation.