Labour veteran Annette King has confirmed she will stand again in 2017 but possibly only on the list, a step which would open up her Rongotai electorate for leader Andrew Little.
Mr Little is currently a list MP and if he does not win an electorate he could be the first Prime Minister who is not also an electorate MP.
Although the party vote determines a party's representation in Parliament under MMP, there is still some moral weight in being able to win an electorate and Labour is unlikely to want to take any risks.
Mr Little lives in the Rongotai electorate in Wellington - a safe Labour seat in which Ms King has been the local MP since 1993.
Asked if Mr Little had asked her to allow him to stand in the seat, Ms King said "that is hypothetical".