Ministers in the New Zealand Government in the context of "Members of Parliament"

The Colony of New Zealand was a colony of the United Kingdom from 1841 to 1907. British authority was vested in a governor. The colony had three successive capitals: Okiato (or Old Russell) in 1841; Auckland from 1841 to 1865; and Wellington from 1865. Following the New Zealand Constitution Act 1852, the colony became a Crown colony with its first elected parliament in 1853. Responsible self-government was established in 1856 with the governor required to act on the advice of his ministers. In 1907, the colony became the Dominion of New Zealand.

The governor-general of New Zealand (Māori: Te kāwana tianara o Aotearoa) is the representative of the monarch of New Zealand, currently King Charles III. As the King is concurrently the monarch of 14 other Commonwealth realms and lives in the United Kingdom, he, on the advice of his New Zealand prime minister, appoints a governor-general to carry out his constitutional and ceremonial duties within New Zealand.

Governors-general typically serve a five-year term of office, subject to a possible short extension, though they formally serve "at the monarch's pleasure". The incumbent governor-general is Dame Cindy Kiro, since 21 October 2021. Administrative support for the governor-general is provided by the Department of the Prime Minister and Cabinet. Constitutional functions include presiding over the Executive Council, appointing ministers and judges, granting royal assent to legislation, and summoning and dissolving parliament. These functions are generally exercised only according to the advice of an elected government. The governor-general also has important ceremonial roles: hosting events at Government House in Wellington, and travelling throughout New Zealand to open conferences, attend services and commemorations, and generally provide encouragement to individuals and groups who are contributing to their communities.

The constitution of New Zealand is the sum of laws and principles that determine the political governance of New Zealand. Unlike many other nations, New Zealand has no single constitutional document. It is an uncodified constitution, sometimes referred to as an "unwritten constitution", although the New Zealand constitution is in fact an amalgamation of written and unwritten sources. The Constitution Act 1986 has a central role, alongside a collection of other statutes, orders in Council, letters patent, decisions of the courts, principles of the Treaty of Waitangi, and unwritten traditions and conventions. There is no technical difference between ordinary statutes and law considered "constitutional law"; no law is accorded higher status. In most cases the New Zealand Parliament can perform "constitutional reform" simply by passing acts of Parliament, and thus has the power to change or abolish elements of the constitution. There are some exceptions to this though – the Electoral Act 1993 requires certain provisions can only be amended following a referendum.

After decades of self-governance, New Zealand gained full statutory independence from Britain in 1947. It is a constitutional monarchy with a parliamentary democracy. The monarch of New Zealand is the head of state – represented in the Realm of New Zealand by the governor-general – and is the source of executive, judicial and legislative power, although effective power is in the hands of ministers drawn from the democratically elected New Zealand House of Representatives. This system is based on the "Westminster model", although that term is increasingly inapt given constitutional developments particular to New Zealand. For instance, New Zealand introduced a unicameral system within a decade of its statutory independence.

The New Zealand Government (Māori: Te Kāwanatanga o Aotearoa) is the central government through which political authority is exercised in New Zealand. As in most other parliamentary democracies, the term "Government" refers chiefly to the executive branch, and more specifically to the collective ministry directing the executive. Based on the principle of responsible government, it operates within the framework that "the [King] reigns, but the government rules, so long as it has the support of the House of Representatives". The Cabinet Manual describes the main laws, rules and conventions affecting the conduct and operation of the Government.

Executive power is exercised by ministers, all of whom are sworn into the Executive Council and accountable to the elected legislature, the House of Representatives. Several senior ministers (usually 20) constitute a collective decision-making body known as the Cabinet, which is led by the prime minister (currently Christopher Luxon). A few more ministers (usually junior or supporting) are part of the Executive Council but are outside Cabinet. Most ministers have a portfolio of specific responsibilities such as departments or policy areas, although ministers without portfolio can be appointed.

The prime minister of New Zealand (Māori: Te pirimia o Aotearoa) is the head of government of New Zealand. The incumbent 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 Department of the Prime Minister and Cabinet (DPMC; Māori: Te Tari o te Pirimia me te Komiti Matua) is the central public service department of New Zealand, charged with providing support and advice to the Governor-General, the prime minister and members of the Cabinet of New Zealand. DPMC is also charged with centrally leading New Zealand's "national security planning, which includes civil defence." The department's overall area of responsibility is in helping to provide, at an administrative level, the "constitutional and institutional glue" within New Zealand's parliamentary democracy. The department along with the Public Service Commission, and the Treasury constitute the central agencies or public service departments leading the state sector of New Zealand.

The Executive Council of New Zealand (Māori: Te Komiti Matua o Aotearoa) is the full group of "responsible advisers" to the governor-general, who advise on state and constitutional affairs. All government ministers must be appointed as executive councillors before they are appointed as ministers; therefore all members of Cabinet are also executive councillors. The governor-general signs a warrant of appointment for each member of the Executive Council, and separate warrants for each ministerial portfolio.

To be an executive councillor, one must normally be a member of Parliament (this was codified in the Constitution Act of 1986). However, one may serve up to thirty days without being in Parliament; this is to allow for the transition of members not yet sworn in and members who have retired or been defeated. Each executive councillor must take the relevant oaths or affirmations set out in legislation.

The House of Representatives is the sole chamber of the New Zealand Parliament. The House passes laws, provides ministers to form the Cabinet, and supervises the work of government. It is also responsible for adopting the state's budgets and approving the state's accounts.

The House of Representatives is a democratic body consisting of representatives known as members of parliament (MPs). There are normally 120 MPs, though there are currently 123 due to overhang seats. Elections take place usually every three years using a mixed-member proportional representation system, which combines first-past-the-post elected seats with closed party lists. 72 MPs are elected directly in single-member electoral districts and further seats are filled by list MPs based on each party's share of the party vote. A government may be formed from the single party or coalition of parties that has the support of a majority of MPs. If no majority is possible, a minority government can be formed with a confidence and supply arrangement. If a government is unable to maintain the confidence of the House then an early general election can be called.