via Wikipedia:
The 2020 New Zealand general election will be held after the currently elected 52nd New Zealand Parliament is dissolved or expires. Prime Minister Jacinda Ardern has announced the election date as Saturday 19 September 2020.
Voters will elect 120 members to the House of Representatives under New Zealand's mixed-member proportional (MMP) voting system, a proportional representation system in which 72 members are elected from single-member electorates and 48 members are elected from closed party lists.
After the previous election, the centre-left Labour Party, led by Prime Minister Jacinda Ardern, formed a minority coalition government with the New Zealand First party, with confidence and supply from the Green Party. The main opponent to the Labour–NZ First government is the centre-right National Party, led by Todd Muller. The ACT Party is the sole other party in Parliament, represented by a single MP.
Because of the possibility of overhang under the MMP system, this question resolves as the number of seats held by Labour divided by the total number of seats in the House, expressed as a percentage.