Prime Minister of New Zealand

The prime minister of New Zealand (Māori: Te pirimia o Aotearoa) is the head of government of New Zealand. The incumbent^[update] prime minister, Christopher Luxon, leader of the New Zealand National Party, took office on 27 November 2023.

The prime minister (informally abbreviated to PM) ranks as the most senior government minister. They are responsible for chairing meetings of Cabinet; allocating posts to ministers within the government; acting as the spokesperson for the government; and providing advice to the sovereign or the sovereign's representative, the governor-general. They also have ministerial responsibility for the Department of the Prime Minister and Cabinet, which is based in the Beehive in Wellington.

The office exists by a long-established convention, which originated in New Zealand's former colonial power, the then United Kingdom of Great Britain and Ireland. The convention stipulates that when the office becomes vacant, the governor-general must select as prime minister the person most likely to command the support, or confidence, of the House of Representatives. This individual is typically the parliamentary leader of the political party that holds the largest number of seats in that house. The prime minister and Cabinet are collectively accountable for their actions to the governor-general, to the House of Representatives, to their political party, and ultimately to the national electorate.

Originally the head of government was titled "colonial secretary" or "first minister". This was changed in 1869 to "premier". That title remained in use for more than 30 years, until Richard Seddon changed it to "prime minister" in 1900 during his tenure in the office. Following the declaration of New Zealand as a Dominion in 1907, the term prime minister was adopted. In Māori, the term pirimia is derived from English premier and means prime minister or premier. New Zealand prime ministers are styled as "The Right Honourable", a privilege they retain for life.

Forty-two people (thirty-nine men and three women) have served as prime minister, the first being Henry Sewell, who took office on 7 May 1856 as premier. The longest-serving prime minister was Richard Seddon, who served over 13 years, and the shortest-serving was Sewell, who served two weeks.

The governor-general appoints a prime minister, like other ministerial positions, on behalf of the monarch. By the conventions of responsible government, the governor-general will call to form a government the individual most likely to receive the support, or confidence, of a majority of the elected members of parliament (MPs). In making this appointment, convention requires the governor-general to act on the outcome of the electoral process and subsequent discussions between political parties by which the person who will lead the government as prime minister is identified. In practice, the position typically falls to an MP who is the parliamentary leader of the largest political party among those forming the government. The prime minister may lead a coalition government and/or a minority government dependent on support from smaller parties during confidence and supply votes.

Once appointed and sworn in by the governor-general, the prime minister remains in the post until dismissal, resignation, or death in office. They, like all ministers, hold office "during the pleasure of the Governor-General", so theoretically, the governor-general can dismiss a prime minister at any time; however, convention heavily circumscribes the power to do so. The governor-general retains reserve powers to dismiss a prime minister in certain circumstances, such as those pertaining to a no-confidence motion against the government in the House of Representatives.

Where a prime minister, and by extension, the government, can no longer command the confidence of the house, either by losing a confidence vote or as the result of an election, convention dictates that they should tender their resignation to the governor-general. Under the Constitution Act 1986, general elections are required every three years, setting the maximum period a prime minister can serve without their mandate being renewed.