Labour MP Phil Goff will announce he is standing for the Auckland Mayoralty on November 22 at a function at Westhaven.
Two sources in the Goff camp have confirmed to the Herald the date and location of the announcement.
Today at Parliament, Mr Goff said he had been saying for some time that he would be making an announcement before Christmas.
"I've stuck by that position for the last several months, and I anticipate that will happen in a few months' time."
Mr Goff hinted that his campaign platform could be based on improving transport and housing and minimising wasteful spending.
"I can't talk about campaign plans before any announcement is made. But [Aucklanders] want to see real progress made towards the goals of the Super City, which was the elimination of waste and duplication. That has got to happen."
It is understood that David Lewis, a former chief press secretary to Prime Minister Helen Clark and adviser to Mayor Len Brown at the last two elections, will be Mr Goff's campaign manager.
The confirmation that Mr Goff is seeking the mayoralty is a huge blow for Mayor Len Brown, who has lost the backing of key members of his previous campaign teams, including Mr Lewis.
At the weekend, Mr Brown told TVNZ's Q + A programme and TV3'S The Nation he would be making a statement in the very near future about his plans. He said his nine years as mayor - three as Manukau City mayor - had been hugely challenging on his personal life as well as his working life.
Last Friday, Mr Brown hosted a private BYO function at the Cloud on Auckland's waterfront for 30 to 40 present and past staff in the mayoral office.
One source at the function said he gave no indication one way or another about his plans.
"Surely it is dawning on him this is not going to happen next year. People that supported him last time have made it pretty clear what he should do.
"If he did step down he would be free of all the negativity and be able to focus on all the good things and his legacy," the source said.
The confirmation that Mr Goff will stand for the mayoralty sparked a discussion on social media.
Albert-Eden-Roskill councillor Cathy Casey, Albert-Eden-Roskill Local Board chairman Peter Haynes and his deputy Glenda Fryer - all members of the left-leaning City Vision ticket - welcomed the announcement on Facebook
"Go Mayor Phil Goff", Ms Casey said.
Jason Bryant said Mr Goff would continue his "80s rogernomics wet dream" and sell Auckland down the drain.
"I would like a candidate from the Green Party to represent the left. Goff is as far right as Key and (Cameron) Brewer," he said.
Former Labour MP Moana Mackey said he was absolutely not like Key and Brewer.
"His values are Labour values and his work ethic is second to none."
Prime Minister John Key told media in Auckland today that if Mr Goff was to announce he would run for mayor it would be "no great surprise".
"Phil Goff's been a passionate Aucklander for a long period of time," Mr Key said.
He said the Government would have to work with whoever became mayor, regardless of previous political standing.
"We are committed to Auckland, Auckland is the place where we need to continue to resolve issues like housing and other social services, so we have to work with the council there.
"His strengths are obviously he's had a long time in government ... so clearly he's got a high work rate, I don't think anyone has doubted that," Mr Key said.
The Taxpayers' Union has called on Mr Goff to resigned from Parliament when he announces his tilt at the mayoralty.
Executive director Jordan Williams said: "Taxpayers won't tolerate a situation where Mr Goff is paid to be an MP in Wellington, but is instead campaigning to be Labour's new mayor in Auckland."
The Auckland Ratepayers' Alliance welcomed the expected announcement from Mr Goff.
Spokeswoman Carmel Claridge said while many members would welcome Labour replacing Mr Brown for another candidate, "we need to see a credible plan to end Auckland Council's high rates, high debt, trajectory".
"Right now Auckland Council owes creditors more on a per person basis than any other council in New Zealand. Even Christchurch ratepayers have a smaller per capita debt burden."
"All Super City mayoral candidates will need credible plans which set out how they are going to pay for their promises. If Mr Goff is running on promises of transport spending, we just want to know how he plans to pay for it. After 9.9% rate hikes and with more borrowing out of the question, dipping deeper into ratepayers' pockets isn't an option," Ms Claridge said.
- Additional reporting: Sophie Ryan