Former Labour MP John Tamihere has threatened to appeal the party's decision to refuse to renew his membership.
Mr Tamihere said he had not been given a reason for the decision but he believed it was because he was contesting the Auckland mayoralty and Labour had endorsed the incumbent mayor, Phil Goff, who was expected to run again.
The party's constitution specifically forbids members from running or campaigning against candidates it has endorsed, but Mr Tamihere said that rule did not apply because Mr Goff had not yet revealed if he was running for re-election.
"You can't endorse a guy who is yet to determine whether he wants to be a candidate. That's endorsing an apparition."
Mr Tamihere said he did not believe previous problems had prompted the council to reject his application.
In 2005 he made derogatory comments about women and gay people in then-prime minister Helen Clark's caucus and in 2013 he was condemned for victim-blaming in an interview with a woman in the Roastbusters sexual assault scandal.
He said neither matter was relevant now. "You either get denied membership at the time of those matters or you don't, right. Neither of those two counted against me in terms of renewal of membership. If you recall, [Michael] Cullen and Clark came out of our caucus on the first issue that you've raised and indicated that the party is a forgiving party."
Mr Tamihere said his decision to make his run for mayoralty in partnership with former National Party MP Christine Fletcher also should not count against him.
"That's none of their business. What is part of their business is that I'm running on a very strong principled policy that upholds social housing, that upholds greater clarity around expenditure, that upholds that people earning under $80,000 a year in Auckland have a justifiable right not to be used as Goff's ATM. Those are fair principles that anyone in the rank and file of the Labour Party would acknowledge are right.
Mr Tamihere said he had yet to decide if he would appeal the party's decision. "If push comes to shove, I'd rather be mayor of Auckland than a member of the Labour Party."
Rudy Taylor from Labour's Māori council, Te Kaunihera Māori, said the party's ruling council should have given Mr Tamihere a second chance.
"I thought he should be given a second chance. If you're talking about natural justice, bring the guy in so he can spell it out."
Mr Taylor said the council should have considered Mr Tamihere's past contributions to Labour. "We should have taken on board what he's given to the Labour Party," he said.
"John wanted to be a member only so he could get that support... but the council had decided to go with Phil Goff."
Mr Taylor said he would like to give Mr Tamihere the chance to put his case to Te Kaunihera in person.
Former Māori Affairs Minister and Labour Party life member Dover Samuels said there was something not right about the party denying Mr Tamihere's membership renewal.
Mr Samuels was at a meeting of Labour's Māori council, Te Kaunihera Māori, at Waitangi where the continued membership of Mr Tamihere came up.
He said the way Labour's treated Mr Tamihere could cost the party some of its Māori support and the refusal of his application "doesn't smell right".
Prime Minister Jacinda Ardern refused to comment.
"That's ultimately a question for New Zealand council, it's not something I'm involved with at all. They're the ones that consider applications to rejoin the party and that's what they've done here, but it's not something I've been involved with," she said.
A spokesperson for Auckland Mayor Phil Goff said he was grateful for the Labour Party's endorsement and Mr Tamihere's party membership was a matter for the party.
Mr Goff will make a campaign-related announcement on Sunday.