Yes the New Zealand government thought it was in their interest to help against the encroachment of communism
However as wildcat pointeds out it wasn't under any immediate threat, 1000 miles from the nearest land, and this being Australia. To protect against invasion, given the logistical difficulties, New Zealand could only need a small miklitary, and not worry about anything else...
What about the parts of WWI and WWII when New Zealand contributed disproportionatly :
Wiki on WWI
The total number of New Zealand troops and nurses to serve overseas in 1914-1918, excluding those in British and other Dominion forces, was 103,000, from a population of just over a million. Forty-two percent of men of military age served in the NZEF. 16,697 New Zealanders were killed and 41,317 were wounded during the war - a 58 percent casualty rate. Approximately a further thousand men died within five years of the war's end, as a result of injuries sustained, and 507 died whilst training in New Zealand between 1914 and 1918. New Zealand had one of the highest casualty and death rate per capita of any country involved in the war (Serbia suffered even higher per capita losses).
Wiki on NZ in WWII
The costs for the country were high - 11,625 killed, a ratio of 6,684 dead per million in the population which was the highest rate in the Commonwealth (Britain suffered 5,123, Canada suffered 3,750 and Australia 3,232 per million population).