New Zealand's Labour government establishes a national nuclear-free zone under the New Zealand Nuclear Free Zone, Disarmament, and Arms Control Act 1987.

New Zealand is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island and the South Island —and over 600 smaller islands. It is the sixth-largest island country by area and lies east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The country's varied topography and sharp mountain peaks, including the Southern Alps, owe much to tectonic uplift and volcanic eruptions. New Zealand's capital city is Wellington, and its most populous city is Auckland.

The Fourth Labour Government of New Zealand governed New Zealand from 26 July 1984 to 2 November 1990. It was the first Labour government to win a second consecutive term since the First Labour Government of 1935 to 1949. The policy agenda of the Fourth Labour Government differed significantly from that of previous Labour governments: it enacted major social reforms and economic reforms.

In 1984, Prime Minister David Lange banned nuclear-powered or nuclear-armed ships from using New Zealand ports or entering New Zealand waters. Under the New Zealand Nuclear Free Zone, Disarmament, and Arms Control Act 1987, territorial sea, land and airspace of New Zealand became nuclear-free zones. This has since remained a part of New Zealand's foreign policy.

In 1987, the Fourth Labour Government passed the New Zealand Nuclear Free Zone, Disarmament and Arms Control Act. The Act essentially declared New Zealand as a nuclear free zone. The purpose of the Act was ambitious and wide-ranging: “to establish in New Zealand a Nuclear Free Zone, to promote and encourage an active and effective contribution by New Zealand to the essential process of disarmament and international arms control”.