The Auckland Council will be taken to court over its decision to ban two right-wing speakers from using a council venue for a seminar next month.
On Friday mayor Phil Goff said venues should not be used to stir up ethnic or religious tensions and banned Canadian speakers Lauren Southern and Stefan Molyneux from using the Bruce Mason Centre.
"Southern and Molyneux are free to speak at a private venue of their choosing. However, I would be concerned about Auckland Council providing a venue for people who insult or abuse the faith or ethnicity of others," Mr Goff said.
"Both have a track record of making comments seemingly designed to insult and provoke ethnic and religious groups against whom they were made."
A crowdfunding campaign, run by the Free Speech Coalition, to bring judicial proceedings against the council was started only 24 hours ago but has since raised more than $50,000.
Coalition spokesperson David Cumin said it would set a precedent in defending the rights of New Zealanders to express and hear controversial views.
"This is a freedom of speech issue. I don't think most Kiwis are going to necessarily agree with the speakers but we'll fight to their right to speak, and that's really the important point here," he said.
"The more speech we have from reasoned sensible people the better our society is and allowing extreme speech is part of that as well."
Former National Party leader Don Brash, a member of the Free Speech Coalition, said the group hoped to force Mr Goff to recognise he is in breach of the Bill of Rights and the Human Rights Act.
"The council platforms are paid for by all ratepayers, not by Phil Goff, and I think it's important the council facilities which are paid for by all ratepayers are available to people with a wide range of political views."
Dr Brash accepted that the views previously expressed by one of the activists were racist but defended their right to make them.
Lauren Southern said the pair planned to speak on 3 August on a range of issues, including "immigration, the preservation of western culture and the infectious liberal or far-left ideologies that are coming and working their way into our media".
Mr Cumin said he was hopeful the pair would be "un-banned" and could resume that plan.
"I think regardless of what political opinion you have, your freedom to voice that opinion particularly in a public venue is really a cornerstone of our freedom and our democracy and for [Mr Goff] to undermine that is a real travesty and needs to be fought."
Even if the council were to now allow the pair to speak at the Bruce Mason Centre, the court action would go ahead.
"This is an important test case so we'll continue to make sure this is followed through," he said.
He said the council had potentially breached the Bill of Rights Act and the Human Rights Act.
"The Human Rights Act forbids discrimination based on political opinion which, on the face of it, is clearly what he was doing with his tweet, so I think it's an extremely intolerant perspective and it's possibly illegal as well so we'll test that."
The Coalition received more than 700 donations, the largest being for $5000.
In response to the possible action, Mr Goff said the decision to prevent the speakers from talking at a council venue was made in light of concerns.
"Auckland Live concluded that to have gone ahead with hosting the event would have been potentially a security risk to people and property," Mr Goff said.
"Auckland Council will respond to any judicial proceedings if and when they occur."