Green Party list MP Denise Roche is facing a challenge for the Auckland Central selection from political newcomer Chloe Swarbrick.
The party's nominations for the Auckland Central seat closed yesterday and Swarbrick and Roche are the only candidates to put their names forward. The Greens will select a candidate on February 13.
Swarbrick, who runs a digital marketing business, joined the Greens after placing third in the Auckland mayoral contest. She came from nowhere to claim nearly 30,000 votes after running a campaign based on a strong social media presence.
She has previously said that she not only wants to stand in an Auckland seat but to win one.
"I am really keen to run somewhere where I can actually run to win."
Roche, who is the Greens' industrial relations and workplace safety spokeswoman, placed third in Auckland Central in the 2014 general election with 2082 votes, nearly 1000 votes fewer than 2011.
However, the Greens focus most of their energy on the party vote and Auckland Central is a key electorate for them. They won more votes than Labour there in 2014.
National MP Nikki Kaye held onto the seat with a 600-vote majority over Labour's Jacinda Ardern in the closest race in the country.
Kaye will defend her seat again while Ardern is instead competing for the safe Labour seat of Mt Albert in a byelection on February 25.
Kaye recently returned to work after receiving treatment for breast cancer, and is tipped to take over as Education Minister from Hekia Parata in May, further boosting her profile.
Labour's nominations for Auckland Central close today, and among those considering a bid is former Internet Party leader Laila Harre, who rejoined Labour late last year.
There had been speculation that either Labour or Greens could step aside in Auckland Central to give the other party a clear run at unseating Kaye.
But Labour leader Andrew Little confirmed for the first time today that no electoral deals would be made in Auckland Central or any other seat.
"We are agreed that we are not going to have agreements on electorate accommodations, so what each party will do in each electorate will be their decision," he told RNZ National.
"We've had discussions about it. In the end, we got to the point where they want electorate candidates so that they can campaign for the party vote, we want electorate candidates because we want to campaign for both the electorate and the party vote."