New Zealand combat involvement in Vietnam began with the arrival in Saigon of the 161st Battery, RNZA, equipped with L5 pack howitzers, in July 1965. The personnel and their equipment were conveyed to the theatre by RNZAF C130 aircraft - the first occasion a New Zealand unit had been deployed in a war zone with full equipment by air. The gunners were based at Bien Hoa air base, where they provided support to the American 173rd Airborne Brigade, under whose operational control they were placed. After preparing facilities for them, the engineer detachment was withdrawn to New Zealand.
The battery was involved in seventeen major operations, mainly around Bien Hoa but also including two sorties into Phuoc Tuy province to the south. During 1966 it was brought up to six-gun strength and, in June, passed to the operational control of 1st Australian Task Force, which was established at Nui Dat in Phuoc Tuy province. In August 1966 the gunners played a key role in assisting Australian infantry of 6th Battalion, Royal Australian Regiment, during the important action at Xa Long Tan, in which 18 Australians were killed holding off a regimental sized enemy force.
Once 'Confrontation' ended and Australia decided, in December 1966, to expand 1st Australian Task Force to a brigade strength, New Zealand came under new pressure to increase its commitment. In April 1967 V Company was deployed from New Zealand's infantry battalion in West Malaysia, to be followed in December by W Company. From this time the battalion was almost exclusively focused on supporting the infantry involvement in Vietnam.
The New Zealand companies operated at first under the operational control of 2nd Battalion, RAR. From March 1968 they were integrated within 2RAR to form 2RAR/NZ (ANZAC) Battalion, with New Zealand personnel assuming various positions in the battalion, including that of second in command. A similar arrangement was made with 4RAR when it relieved 2RAR in May 1968, and then successively with 6RAR and 2RAR until the end of the two countries' combat commitment.
Although convenient for New Zealand, given the small size of its infantry contingent, and reasonably effective in practice, the integration meant that the New Zealand identity of the units, and the artillery, tended to be overshadowed by the Australians. For the New Zealand infantrymen, the operations were a constant round of patrols or cordon and search operations. Large-scale actions were uncommon. The objective, to seize the initiative in the province, was largely achieved, and the provincial enemy forces were rendered largely ineffective without outside support.