Social Development Minister Paula Bennett has reclaimed the Waitakere seat from Labour's Carmel Sepuloni by nine votes in a judicial recount.
Official confirmation is expected later today.
Ms Bennett was named the winner of the electorate on election night after the results gave her a 349-vote lead over Ms Sepuloni.
However, the National MP lost the seat in last Saturday's special vote count, which gave Ms Sepuloni an even tighter margin of 11 votes.
Ms Bennett applied for a judicial recount.
The result is particularly disappointing for Ms Sepuloni, who loses her place in Parliament altogether because her ranking is too low for her to come in on Labour's list.
Waitakere was traditionally a Labour seat until Ms Bennett took it from Labour's Lynne Pillay in 2008, who had held it for two terms.
Ms Sepuloni was not considered a gracious winner after reclaiming the seat for Labour last week, saying the result had been a clear message of discontent at Ms Bennett and the hard-line welfare policies she had been pushing.
"I don't think Paula Bennett has been good for Waitakere," Ms Sepuloni said.
"At the end of the day, the voters have spoken. And despite the fact it is close, it just goes to show that there are 11 more people that think she wasn't' (good)."