What is a by-election?
There are two ways that a person could be elected to Parliament:
- As an electorate MP, elected to represent a particular geographical area (an electorate)
- As a list MP, elected based on how many votes their party won.
A by-election is held when an electorate seat becomes vacant between general elections. There are a number of ways this can happen, but most often when an MP resigns or retires from Parliament.
By-elections only occur with the departure of an electorate MP. If a list MP resigns, the next candidate on their party list is invited to replace them.
There is no party vote in a by-election. The public vote to elect a new electorate MP, and only people registered to vote in that electorate can do so. During this parliamentary term there has only been one by-election. That was for the Northcote electorate on 9 June 2018. So far, the other MPs who have resigned during the 52nd Parliament were all list MPs. When they resigned, the next four MPs on the National Party list came into Parliament.
When an electorate seat becomes vacant between elections, some constitutional procedures must be followed. The Speaker of the House must publish a vacancy notice in the New Zealand Gazette (the official newspaper of the New Zealand Government), The Speaker also advises the House of the vacancy. Within 21 days, the Governor-General will issue a writ instructing the Electoral Commission to hold a by-election. The return of the writ shows the name of the person elected as the new electorate MP.
Bye, but no by-election
When an electorate MP resigns within six months of a general election, Parliament can choose not to hold a by-election.
Doing this requires the House to pass a motion that no writ be issued for a by-election. The motion requires the support of 75% of MPs.
Unnecessary cost is the main reason for avoiding a by-election in the six months before a general election. Not holding a by-election can save hundreds of thousands of dollars for a result which would be reviewed in a few months during the next general election.