Prime Minister Chris Hipkins has selected November 25 as the date for the Port Waikato by-election.
The by-election was triggered on Monday by the death of ACT candidate Neil Christensen.
The death of a candidate before the general election means only the party votes in the electorate get counted on October 14, and not the electorate candidate votes. A separate by-election is necessary to choose the electorate's MP.
The power to choose a by-election date lies with the Prime Minister. Given the proximity of the election - which National is favoured to come out on top of - Hipkins consulted with other political leaders when choosing the date.
"Following consultation with other political parties I’ve confirmed November 25th as the by-election date,' Hipkins said.
"Everyone was of the view it should occur at the earliest possible time."
The by-election Writ Day will be Monday 16 October. The deadline for candidate nominations to be received will be midday Friday 20 October, and the last day for the return of the Writ will be Friday 15 December.
The addition of the by-election will likely result in an extra seat in Parliament for the National Party.
When the results of the October 14 election are revealed, they will be based on a 120-seat Parliament. However, rather than there being 72 electorate seats and 48 List MPs, there will be 71 electorate seats and 49 List MPs. The number of electorate seats could be impacted by an overhang.
Once the by-election has been held, the additional electorate MP will come into the Parliament, meaning there will be 121 seats.
Port Waikato is currently held by National's Andrew Bayly. In 2020, Bayly received 39.4 percent of the vote compared to the Labour candidate's 28.5 percent. The ACT candidate received 3.4 percent.
As Bayly is ranked 16th on National's List, it's likely he will enter Parliament after Saturday, even though there is no electorate contest. If he was to win the by-election, which he would be expected to, he would become an electorate MP, opening up his List position to another National candidate.
Bayly said on Monday: "I want to offer my condolences to Patricia and the family of Neil Christensen. Neil was an energetic campaigner for ACT and one of New Zealand's pre-eminent poultry vets. It's a terrible loss for the family and Franklin."
Chief electoral officer Karl Le Quesne said on Monday the commission's thoughts were with Christensen's family.
"It is an unusual situation for a candidate to pass away before election day, and the Electoral Act sets out what happens next."
He said Port Waikato voters who haven't voted, should still go and vote. If they have already voted, they don't need to do anything else.
"Your party vote will be counted and contribute to the overall results of the General 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."
ACT leader David Seymour said Christensen was a valued member of the party.
"On behalf of the ACT Party, I’d like to offer my condolences to Neil’s family and friends. Our thoughts are with you," he said.
"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 was a dedicated member of the ACT Party who will be immensely missed."
Christensen was born in the United Kingdom and grew up in Africa. He moved to New Zealand in 1984. He began working in poultry veterinary in 1979 and was New Zealand's only registered specialist poultry vet.
