Auckland Mayor Len Brown is not standing again, leaving the field open for contenders that are likely to include Labour MP Phil Goff.
"I'm happy to confirm that I will not be seeking nomination for the Auckland mayoralty in next year's election," he told TVNZ's Q&A program today.
Mr Brown is the first mayor of the Auckland super city and was a previous Manukau mayor.
He said after two terms leading the merged Auckland Council "I've decided that's enough".
Labour leader Andrew Little told Q&A it was the right decision for Auckland and he would not be drawn on ramifications for his party if Mr Goff became Auckland's mayor.
On Thursday, 3 News reported Mr Goff had taken on Helen Clark and Mr Brown's former spin doctor David Lewis and booked a venue for November 22 to make the announcement.
The veteran politician is the MP for the Auckland electorate of Mt Roskill, has served as a cabinet minister and led Labour to defeat at the 2011 general election.
If he decided to run for mayor Labour would need to decide who it would put up in a by-election in his electorate.
In 2013, Mr Brown was at the centre of a sex scandal but he remains with his wife Shan Inglis.
Mr Brown said he wanted to put an end to speculation about his future.
"To Phil (Goff) and anyone else who wants to run I offer them nothing but the very best of luck," he said.
"It's a job with extraordinary opportunity but major challenges."
Christchurch's mayor Lianne Dalziel has said she's "leaning on the side of yes", while Wellington's Celia Wade-Brown has said she will probably stand again in next year's vote.
Sources: Local Government New Zealand, Statistics NZ, Auckland Council