It could end speculation of a hung parliament forcing a second election, and instead see the electorate take on the role of ‘kingmaker’.

Residents in Port Waikato will be heading back to the polls after this weekend’s election. 

The unexpected death of Act Party candidate Neil Christensen, who was on the ballot in the seat, has triggered section 153A of New Zealand’s Electoral Act. 

Act leader David Seymour acknowledged the passing of Christensen this afternoon, calling him a dedicated member of the party who would be immensely missed. “I wish to pay tribute to Neil, who was an infectiously charismatic and fascinating man and was New Zealand’s only registered specialist poultry veterinarian,” he said in a statement.

“On behalf of the Act Party I’d like to offer my condolences to Neil’s family and friends. Our thoughts are with you.”

A byelection means voting for the local candidate in Port Waikato will be suspended and any electorate votes already cast during the advance voting period will be nullified. A byelection will take place at a later date.

“For voters in the Port Waikato general electorate – if you haven’t voted yet, please go and vote. If you have already voted, you don’t need to do anything more,” said the chief electoral officer Karl Le Quesne.

Party votes in the electorate will still be counted and contribute to the overall results of the election. “Your vote is important. You will have an opportunity to vote for a member of parliament for the Port Waikato electorate when a by-election is held.”

While this means that Port Waikato locals won’t have a new MP on the morning of October 15, it doesn’t mean there will be an empty seat in parliament’s debating chamber. Our mixed member proportional – MMP – system will ensure that parliament still has all 120 seats filled based on the country’s party vote allocation. The number of seats will be calculated as though there was no winner for Port Waikato, explained constitutional expert Andrew Geddis.

“The Electoral Commission must allocate a total of 120 seats amongst parties that cross the representation threshold after the general election (less any seats won by an independent candidate),” Geddis told The Spinoff. “The by-election in Port Waikato will then return an additional MP.”

The Electoral Commission has since confirmed this, adding that the prime minister – whoever that is after Saturday – will determine the date for the byelection.

This means that the next parliament will, once the byelection has been held, have at least 121 seats. 

Given the ongoing discussion over a possible “second election”, this will potentially remove the option of a hung parliament as 121 seats cannot be split equally between the left and right blocs of parliament.

If the election is as close as the polls and political leaders are forecasting, this could mean the Port Waikato byelection decides the election outcome by giving a 61st MP to either the right or left bloc – effectively becoming a kingmaker seat. That would give a majority and determine which side of the house was able to govern. 

Unless, as Geddis added, “Te Pāti Māori wins an overhang seat and we get a 61-61 split.” But that’s another story.

If things aren’t quite so close, the byelection will still see one side of parliament pick up an extra MP, which could be very important if the new government only holds a slim majority on election night.

Based on historical precedent, National will pick up the additional seat. The party has won Port Waikato and its predecessor in every election since 1996 and would be the early favourite to win the byelection. Andrew Bayly is the current MP and has been campaigning for reelection.

Bayly told the Herald the passing of Christensen was “pretty devastating” and that he had known his rival outside of politics as well. He would be speaking with Christensen’s family to convey his condolences.