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.