The contention of this thesis is that the United Nations remained a primary focus in New Zealand's pursuit of security between 1945 and 1960 and this was not altered in any significant way by the development of regional security arrangements or changes of government during the period. Throughout this time the pursuit of security was a fundamental objective and it was the UN's value as a security provider which saw it remain vitally important to New Zealand. Such changes as there were in New Zealand security policy between 1945 and 1960 occurred gradually and were not related to changes of government or the advent of regionalism. Continuity rather than change characterized New Zealand's approach to the UN during this period. This thesis is divided into three parts. Part 1 investigates New Zealand security and the UN in the period of the Fraser Labour Government. It will be argued that Labour's approach to the UN during this time stemmed primarily from security considerations. Differences between Labour and National were not substantial and did not make a significant impact on New Zealand's approach to the UN. Part 2 will investigate the relationship between the UN and the growth of regionalism. It will be argued that regionalism was not a development peculiar to the 1950s, or to the National Party's approach to security. The regional emphasis apparent in New Zealand security policy during the 1950s was solidly based on precedents established in Fraser's time and was, furthermore, never strong enough to marginalize the UN. Regionalism was a phenomenon which grew alongside the world organization in the 1940s and was not detrimental to New Zealand's continuing attachment to it. At times regionalism and the UN were perceived as closely related in the pursuit of New Zealand security objectives. Part 3 will demonstrate the continuing commitment to the UN displayed by New Zealand, under National, in the 1950s. The underlying impetus and characteristics of New Zealand security policy in the 1940s remained central in the decade that followed. An analysis of New Zealand's approach to regionalism in the 1950s, and a number of case studies involving New Zealand at the United Nations, will be used to demonstrate the enduring nature of this policy originally fashioned in the mid-1940s.