The Waitakere electorate has see-sawed back to National and Social Development Minister Paula Bennett in a recount but Labour has not ruled out taking an electoral petition to challenge the result.
Ms Bennett has held the seat by nine votes ahead of Labour's Carmel Sepuloni who is now out of Parliament altogether. She had been a list MP for the past term.
Celebrating at home last night Ms Bennett said she was feeling delighted but she had some sympathy for her opponent.
"Actually I know what a loss feels like because that's what I felt last Saturday so I actually feel some sympathy for her because it hurts."
Ms Sepuloni offered her congratulations last night.
"We will take a breather for the next few days and make a decision in due course whether or not we go through with an electoral petition."
She said she would go to Parliament on Monday to collect her belongings and meet the party to make a decision on an electoral petition. But it was unlikely.
Ms Sepuloni was declared the winner by 11 votes in the final declaration a week ago, after the special votes had been counted.
Sitting MP Ms Bennett held the seat on election night by 349 votes, before specials had been counted.
Her election now as a constituency MP instead of a list MP has no effect on National's number of MPs. It still has 59 MPs but slightly more electorate MPs than list MPs.
Ms Sepuloni was too low on the list to be saved by it and is out of Parliament. But in order for Labour to keep its 34 MPs, the next person on Labour's list, Raymond Huo, will be back in Parliament when MPs are sworn in on Tuesday.
The recount was overseen by District Court Judge John Adams and he will issue a judgment next week on why some votes were overturned.
Labour will seek advice from party scrutineers who watched the recount, said general secretary Chris Flatt.
He said the party also wanted advice on whether Ms Bennett would be out of Parliament altogether and could not claim a list seat if the electorate result was overturned on an electoral petition.
Electoral law specialist Graeme Edgeler believes that is the only way to interpret the Electoral Act which says a seat shall become vacant if on an electoral petition the High Court or Court of Appeal declares his or her election void.
Removing such a critical minister in the National Government as Ms Bennett is likely to be a strong incentive for Labour.
Weighing against it would be the cost - probably more than $100,000 - and the fact that even if the petition were successful, Ms Bennett might be able to be returned at the first list vacancy, expected when Lockwood Smith is dispatched to a diplomatic post in the London High Commission later next year.