The Cabinet of New Zealand (Māori: Te Rūnanga o te Kāwanatanga o Aotearoa) is a council of senior Government ministers, responsible to the New Zealand Parliament. Cabinet meetings, chaired by the Prime Minister, occur once a week where vital issues are discussed and government policy formulated. The Cabinet has significant power in the New Zealand political system and nearly all bills proposed by the Cabinet in Parliament are enacted.
All Cabinet ministers also serve as members of the Executive Council. Outside the Cabinet, there is an outer ministry and also a number of non-Cabinet ministers, responsible for a specific policy area and reporting directly to a senior Cabinet minister.
No legislative act established the Cabinet: rather, it exists purely by constitutional convention. This convention carries sufficient weight for many official declarations and regulations to refer to the Cabinet, and a government department exists with responsibility for supporting it (the Department of the Prime Minister and Cabinet). Although Cabinet lacks any direct legislative framework for its existence, the Cabinet Manual has become the official document which governs its functions, and on which its convention rests.
The structure of Cabinet has as its basis the formal institution known as the Executive Council. Most Ministers hold membership of both bodies, but some Executive Councillors – known as "ministers outside Cabinet" – do not have Cabinet positions. The convention of members of the Executive Council meeting separately from the Governor began during Edward Stafford's first tenure as Premier (1856–1861). Stafford, a long-time advocate of responsible government in New Zealand, believed the colonial government should have full control over all its affairs, without the intervention of the Governor. Because the Governor chaired the Executive Council, Stafford intentionally met with his ministers without the Governor present.