It was initially raised as a unit of the Militia from white Australian and European expatriates in New Guinea upon the outbreak of the Second World War in 1939, before being activated for full-time service following the Japanese landings in early 1942.

In the years immediately following the war the Australian Army considered re-establishing a military presence in Papua New Guinea (PNG), although there was some opposition among white settlers to the raising of native units.

[13] The men were all white Australian or European expatriates and were drawn from a wide range of civilian occupations, although the majority were longtime residents and included gold miners, planters, traders and government officials.

[14] Due to the paternalistic concerns of the civilian administration regarding native welfare and unease about providing the indigenous population with arms and military training they were not recruited into the NGVR, although they did serve in the Papuan Infantry Battalion (PIB) from June 1940.

Uniforms consisted of khaki shirts and trousers made from material sent from Australia, while felt hats, bandoliers, leather belts, boots, puttees and brass NGVR shoulder badges were also worn.

[23] In June 1940 the NGVR's establishment was increased to 23 officers and 482 other ranks, although this proved difficult to achieve due to the demands of recruitment for overseas service with the Second Australian Imperial Force, which resulted in a large turn-over of men.

[13] Tasks included protecting the airfields at Lakunai and Vunakanau and the seaplane base in Simpson Harbour, as well as forming "an advanced observation line" to provide early warning of Japanese movements.

[23][25] Meanwhile, Australian defences in Papua remained limited and were centred on Port Moresby, consisting of approximately 1,000 only partially trained Militia from the 49th Battalion, two six-inch coastal guns, a 3.7-inch anti-aircraft battery and a few Consolidated PBY Catalina flying boats, in addition to the locally recruited PIB which was still forming.

Scanlan considered he would need an entire brigade to defend Rabaul, yet with an invasion imminent all he could do was redeploy some of his limited force, while the remaining aircraft were withdrawn to Lae and the airfields cratered.

Realising the Japanese occupation of the north coast settlements of the Huon Gulf was imminent, McNicoll declared a state of emergency, handing over control to the NGVR second-in-command, Major Edmund Jenyns.

A number of supply dumps and observation posts had been prepositioned in the hinterland and these were utilised for the task, while two Vickers machine-guns were subsequently set up to cover the narrow approach up the Bitoi River valley to Mubo.

The company included a number of men who possessed an intimate knowledge of the difficult terrain in the area, and despite limited equipment and supply deficiencies, they were subsequently able to provide invaluable intelligence to the Australian high command.

[55] As the sole representative of government authority, the NGVR also assumed responsibility for several thousand indentured native labourers recruited from the outlying districts who had been left without support and were unable to return to their homes.

[58] A platoon of reinforcements intended for the 2/1st Independent Company subsequently reached Port Moresby in late March following the loss of New Britain and New Ireland and they were sent over the Bulldog Track to support the NGVR instead.

[63] Meanwhile, a force consisting of the 2/5th Independent Company under Major Paul Kneen and supporting units had been tasked with undertaking a limited guerrilla offensive to harass and destroy Japanese personnel and equipment in the Lae and Salamaua area and the Markham Valley.

He assessed that the only course of action available was to maintain a large force in the Bulolo Valley to defend the overland route to Papua, while conducting a number of raids in the area in order to inflict casualties on the Japanese and forestall any advance.

[73][76] In retaliation Japanese aircraft subsequently bombed Wau, Bulolo and Skindiwai on 2 July, killing a number of Australians, destroying some houses and buildings, and driving many native carriers into the bush.

[78] Although the morale of the NGVR remained high, the effect of continuous operations in the harsh terrain with only limited logistic and medical support took their toll, with many falling ill to fever and tropical disease.

With the Japanese trapped in the river valley, the Australians opened fire with four Vickers machine-guns, three Lewis guns and three Brens, inflicting between 50 and 60 casualties, including 12 killed, without loss.

Following a landing near Gona, on the north coast of New Guinea, on the night of 21/22 July, Japanese forces attempted to advance south overland through the mountains of the Owen Stanley Range to seize Port Moresby as part of a strategy of isolating Australia from the United States, resulting in a series of battles during the Kokoda Track campaign.

[87] The Japanese subsequently staged a landing at Milne Bay on the eastern tip of New Guinea on the evening of 25 August 1942 to reduce the Allied airfields that had been established there, further straining the limited resources available to Rowell and preventing him from reinforcing Kanga Force.

[88] Meanwhile, the privations of operating around Mubo and in the Markham Valley continued to take their toll on the Australians, and by early August the bulk of the men forward of Bulolu and Wau were commandos.

[91] While the focus of the campaign in New Guinea shifted to the Milne Bay and Kokoda Track battles in August and September 1942 the NGVR continued to man its posts overlooking the Japanese base areas, patrolling extensively.

[52] Following this, as problems with supply and sickness reduced Fleay's effectiveness, Kanga Force was broken up on 23 April 1943[94] with its individual units becoming part of the 3rd Division, which left Wau to begin the Salamaua-Lae campaign to drive the Japanese from Salamaua.

[26] Its men had come from many walks of life, and while some were too old to join the AIF, or were medically unfit or employed in restricted occupations, they acquitted themselves well in the harsh terrain, with only limited equipment and support, often developing their own tactics.

[101] The battalion played an important role in the period to late May 1942 by maintaining contact with the Japanese, as well as demonstrating to the native population in the Salamaua–Wau–Lae region that the Australians had not been forced out of the area.

[104] In the years immediately following the war the Australian Army considered re-establishing a military presence in PNG, although there was some opposition among the colonial administration and white settlers to the raising of native units, echoing previous concerns.

[117] Yet the small European population and the rapid turnover of staff in local industries continued to limit the manpower available, while the Army preferred to recruit permanent residents such as planters and traders, who represented an even smaller minority.

Yet the cost of flying men to Ambra proved prohibitive and from 1966 annual camps were held at Lae, initially at a wartime facility on the Bumbu River, and later at Igam Barracks.

[122] The Cold War and growing Australian concern about Indonesian intentions during the Indonesia–Malaysia confrontation saw increasing defence resources allocated to PNG during the 1960s, including the raising of a second PIR battalion in 1965.