The Queen is the Head of State
While the New Zealand constitution is not actually written down, it can be found in formal legal documents, in decisions of the courts, and in established conventions. New Zealand operates under a constitutional monarchy, it has a parliamentary system of government, and it is a democracy.
The Constitution Act 1986 recognises the Queen of England, Queen Elizabeth II, as the country’s Head of State and the Governor-General as her appointed representative. The Queen and the Governor-General are an important part of the New Zealand governmental process but they remain politically neutral.
The Governor-General plays an important constitutional role in calling elections, in the opening of Parliament and associated ceremonies, and in the formation of governments.
The Treaty of Waitangi is regarded as the founding document of government in New Zealand.
To see how much New Zealand has changed politically and constitutionally over the years, see the timeline at the Ministry of Culture and Heritage