The Government of New Zealand (Māori: Te Kāwanatanga o Aotearoa), formally Her Majesty's Government in New Zealand, is the administrative complex through which authority is exercised in New Zealand. As in most parliamentary democracies, the term "Government" refers chiefly to the executive branch, and more specifically to the "Ministry" (or administration, in American terminology) directing the executive. Based on the principle of responsible government, it operates within the framework that "the Queen reigns, but the government rules, so long as it has the support of the House of Representatives".
Executive power is exercised by the Prime Minister and Cabinet ministers, all of whom are sworn into the Executive Council to become ministers of the Crown and responsible to the elected House of Representatives. The position of Prime Minister, New Zealand's head of government, belongs to the person who commands the support of a majority of members of parliament in the House of Representatives. In practice, the Prime Minister is determined by size of each political party, support agreements between parties and leadership votes in the party that leads the Government.
The Prime Minister and Cabinet are formally appointed by the Governor-General (who is the Queen's representative in New Zealand). However, the Prime Minister chooses the Cabinet, and by convention, the Governor-General respects the Prime Minister's choices. Cabinet ministers are drawn from elected members of the Prime Minister's party in the House of Representatives. 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 are sometimes appointed. The Prime Minister exercises vast political power, especially in the appointment of government officials and civil servants.