New Zealand is a constitutional monarchy and parliamentary democracy.
The Head of State is Queen Elizabeth II of New Zealand who, on the recommendation of the Prime Minister, appoints a personal representative, the Governor-General, to fulfil the official and ceremonial roles. Governor-Generals of New Zealand are non-partisan and not involved in active government.
The legislature is a unicameral parliament, officially called the House of Representatives.
A parliamentary term is 3 years.
The executive government is the Prime Minister and Cabinet. (It is sometimes referred to as the Crown.) The PM and their cabinet must first have been elected to parliament - since the adoption of mixed member proportional system of voting (1993) coalition and minority governments have become a feature.
Māori (NZ's indigenous people) have the right to choose whether to vote in a general or a Māori electorate. The number of Māori seats in a parliamentary term can change, reflecting the strength of the Māori electoral roll.
The official languages are English, Māori, and New Zealand Sign Language.
New Zealand is part of the common law or Anglo-American legal tradition.
There is a hierarchy of courts of ordinary jurisdiction, supplemented by a number of courts and tribunals with special jurisdictions. See the first link below to understand the various lines of appeal.
From 1840 to 2004 final appeals were heard in London, by the Judicial Committee of the Privy Council. In 2004 a New Zealand Supreme Court was established.