An electorate or electoral district () is a geographical constituency used for electing a member () to the New Zealand Parliament. The size of electorates is determined such that all electorates have approximately the same population.
Before 1996, all MPs were directly chosen for office by the voters of an electorate. In New Zealand's electoral system, 72 of the usually 120 seats in Parliament are filled by electorate members, with the remainder being filled from party lists in order to achieve proportional representation among parties. The 72 electorates are made up from 65 general and seven Māori electorates. The number of electorates increases periodically in line with national population growth; the number was increased from 71 to 72 starting at the 2020 general election.
Terminology
The Electoral Act 1993 refers to electorates as "electoral districts". Electorates are informally referred to as "seats" (), but technically the term seat refers to an elected member's place in Parliament.
Distribution
the Representation Commission determines electorate boundaries. The Commission consists of: Four government officials—the Government Statistician, the Surveyor-General, the Chief Electoral Officer, and the Chairperson of the Local Government Commission. A representative of the governing party or coalition, and a representative of the opposition bloc. A chairperson (often a judge) nominated by the other members (with the exception of Chairperson of the Local Government Commission).
The Representation Commission reviews electorate boundaries after each New Zealand census, which normally occurs every five years. The South Island is guaranteed to have 16 general electorates, and dividing the number of persons in the South Island's general electoral population by 16 determines the South Island Quota which is then used to help calculate the number of Māori electorates and to determine the number of North Island electorates. The number of Māori electorates is influenced by the Māori Electoral Option where Māori voters can opt to be in either a Māori electorate or a general electorate. The percentage of Māori voters opting for the Māori roll determines the percentage of the whole Māori population (of persons claiming Māori ancestry at the previous census) which is then divided by the South Island Quota to calculate the number of Māori electorates. South Island Māori opting for the general roll are included in the population on which the South Island Quota is established. The North Island population (including Māori opting for the general roll) is divided into electorates, each of approximately the same population as the South Island ones. Electorates may vary by no more than 5% of the average population size. This has caused the number of list seats in Parliament to decline as the population is experiencing "northern drift" (i.e. the population of the North Island, especially around Auckland, is growing faster than that of the South Island) due both to internal migration and to immigration.
Although the New Zealand Parliament is intended to have 120 members, some terms have exceeded this quantity. Overhang seats arise when a party win more seats via electorates than their proportion of the party vote entitles them to; other parties are still awarded the same number of seats that they are entitled to, which results in more than 120 seats in total. In 2005 and 2011, 121 members were elected; 122 members were elected in 2008.
History
Originally, electorates were drawn up by the Representation Commission based on political and social links, with little consideration for differences in population. Elections for the New Zealand House of Representatives in the 1850s modelled the electoral procedures used for the British House of Commons, which at that time featured both single-member electorates (electorates returning just one MP) and multi-member electorates (electorates returning more than one MP). Each electorate was allocated a different number of MPs (up to three) in order to balance population differences. All electorates used a plurality voting system. From 1881, a special country quota meant that rural seats could contain fewer people than urban seats, preserving improportionality by over-representing farmers. For the 1905 election the multi-member electorates were abolished. The quota system persisted until 1945.