US pressure for ground troops
As the United States escalated its military involvement, New Zealand and other American allies came under increased pressure to provide combat assistance. An unenthusiastic Holyoake responded to American entreaties in December 1964 by pointing to New Zealand's commitments in Malaysia, where its forces were involved in Confrontation. American plans to introduce ground combat forces (as opposed to the combat advisers previously deployed) were not favoured in Wellington, New Zealand again diverging from the more 'robust' approach taken by Australia.
The debility of the Saigon regime left New Zealand policymakers fearful that Vietnam would become a quagmire for the Western powers, sapping their military power to little purpose. Although at first not following suit when Australia decided to send a battalion, New Zealand eventually, on 24 May 1965, agreed to provide a four-gun field artillery battery of approximately 120 men.
In our national interest?
The potential adverse effect on the ANZUS alliance of not supporting the United States (and Australia) in Vietnam was of paramount importance, but the decision to participate was in line with New Zealand's own national interests of countering communism in South-east Asia and of sustaining a strategy of forward defence. A failure to make a token contribution to the Allied effort in Vietnam would have brought into question the basic assumptions underlying New Zealand's post-war national security policies.
During the next seven years the Holyoake government strove to keep New Zealand's involvement at the minimum level deemed necessary to meet its allies' expectations, not least because it remained sceptical about the likely outcome of external military intervention in Vietnam. New Zealand's meagre military resources, the significant troop contribution in Malaysia, and the absence of any political will to use conscripts were all obstacles to a more substantial effort, as were anxieties about financial costs and domestic criticisms.