Public opinion has softened against Auckland Mayor Len Brown after news broke of his affair, but the majority of people responding to a Herald online poll are still calling for him to resign.

Mr Brown last night said he intended to stay on as mayor and urged residents to stand by him after admitting to a two-year affair with a woman appointed to a council advisory panel - later identified as Bevan Chuang.

Messages have flooded Mr Brown's Facebook page and an unscientific poll on today showed 56 per cent of more than 43,000 respondents believed he should stand down.

The figure has dropped slightly from when news of the news of the scandal went public yesterday and 60 per cent of poll respondents said he should stand down.


Among the messages on Facebook, Lisa Gibbons said: "Yes he should step down. If he can't conduct himself with honesty and integrity in his 'private life', how can we trust him to lead our city with honesty and integrity? Not to mention all of this was done on Council time using Council resources - so it has every bit to do with his work ethics. A vote of no confidence from me - for sure!''

Sharalee Devereux wrote: "Do we really want someone who can break his sacred vows so easily in his personal life working for our city? My answer would be no, if he finds it that easy to do it in his personal life, what is to say he wont find it easy in his work life. I don't trust him''.

However, Angela Bowden wrote: "No, it's got nothing to do with his job at hand or with anyone else for that matter. Leave the guy alone, it's none of anyone else's business''.

In a statement, Mr Brown said he had told his wife - to whom he has been married for more than 20 years - about the affair. Last night, he said he told her last week.

The affair is believed to have started in mid-2011, about a year after Mr Brown's wife was treated for throat cancer.

Ms Chuang, 32, has sworn an affidavit and says she has text messages to back up her claims, according to the report on the Whale Oil site.

Opinions on Auckland's Queen St were divided as to whether Mr Brown should resign.

Andy Leef, said no: "As long as he's doing the job, that's his personal stuff. Look at Bill Clinton, look at what happened to him after Monica Lewinsky - the Americans loved him for it even more.''

Mr Leef said had voted for Mr Brown and would do so again. "He's from south Auckland, that's where I'm from.''

However, Julia Marco said Mr Brown should go: "I think he's got to go now. I do actually like Len Brown but, really, I don't think he can survive this politically''.

"I just think it's a real stain on his character. I really do feel for his family who are caught in the middle.''

Prime Minister John Key says he does not believe Mr Brown's two-year extra-marital affair will destabilise Auckland Council and he is focused on working with him on core council issues.

Mr Key, commenting for the first time this afternoon on the Mayor's sex scandal, said it was "a matter for Len Brown and his family''.

"I'm not going to express a view on that ... In the end, that's the matter for the politician.''

Asked whether he felt Mr Brown's actions could destabilise council at a time when the Government was working with it on crucial housing initiatives, Mr Key said: "No, I don't think so. In the end, Len's got a job to do as the Mayor of Auckland.

"He's always worked very effectively with the Government. From the Government's point of view, we're interested in the things that matter to Auckland, and that is certainly housing ... as is transport, and we'll be talking to Len about those issues, not other issues.''

He added: "I intend to work with him as the Mayor of Auckland, and in the end my job is to work with elected officials and get the job done for Auckland.''

Asked whether Mr Brown had his unequivocal support, Mr Key said: "I've just answered that question.''

The Prime Minister was confident that the scandal had not been publicised or generated by anyone related to the National Party.

"I don't have any details ... the first I heard about it was when I read it on the Whale Oil blog site.''

There has been speculation about whether the affair was made public by Len Brown's opponents in the Auckland mayoral race.

New Zealand First leader Winston Peters said Mr Brown's future "was for the people of Auckland to decide''.

Mr Peters asked why the information was not made public before Mr Brown was elected, and said Aucklanders were entitled to have the information before they decided who their mayor should be.

He said that if Whale Oil blogger Cameron Slater was being "a responsible journalist'', he should have published the information before the mayoral election.

"The so-called informant, or the whistle-blower, if he thinks that he's got integrity on this issue, then he has to answer: Why didn't he let the information go when the people would have had that information before they made their electoral judgement?''

Mr Peters did not accept Mr Slater's explanation that the blogger had been waiting for an affidavit to be signed before the details of the affair were published.