Labour MP Jacinda Ardern is seriously considering a bid for the Mt Albert seat which appears likely to be vacated by David Shearer.
Shearer, the MP for Mt Albert since 2009, has been put forward to head the United Nations' mission in war-torn South Sudan, meaning a by-election could be held in his seat early next year.
Ardern said she was "having a think" about seeking the Labour nomination for Mt Albert if Shearer departed.
"I will be giving it a serious think, it's fair to say that."
She said it was a "really tough call" because she had worked hard in the Auckland Central electorate. She ran unsuccessfully in the seat in 2011 and 2014, coming within 600 votes of National MP Nikki Kaye on the second occasion.
Under boundary changes ahead of the last elections, parts of Auckland Central including Grey Lynn, Arch Hill and Westmere were moved into the Mt Albert electorate.
The shift of those communities to another electorate "felt like a real loss", Ardern said, because she had "spent quite a lot of time working across those communities".
Ardern is considered a potential future leader and Mt Albert would offer the possibility of a safe seat.
"Those are things that naturally you think about," she said.
Its current MP, Shearer, led Labour from 2011 to 2013, and the seat was previously held by Labour Prime Minister Helen Clark.
Kaye is on leave from Parliament while she recovers from breast cancer treatment. She confirmed this week she would run again in Auckland Central at next year's general election.
Kaye has held Auckland Central since 2008, when she beat Labour's Judith Tizard and broke left-wing parties' 90-year hold on the electorate.
Shearer won Mt Albert in 2014 with a 10,000 vote majority over National's Melissa Lee. National won the party vote in the electorate.