Don Brash has called the cancellation of his speaking event at Massey University "utterly astonishing".
The former National Party leader, who formed treaty lobby group Hobson's Pledge, was due to speak at Massey's Manawatu campus on Wednesday, as part of a series of politics talks.
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Vice Chancellor Jan Thomas said "security concerns" were behind the cancellation, but went on to cite concerns about Dr Brash's controversial views.
"Mr Brash's leadership of Hobson's Pledge and views he and its supporters espoused in relation to Māori wards on councils was clearly of concern to many staff - particularly Māori staff," Professor Thomas said.
Mr Brash said the Vice Chancellor didn't even bother to find out what the speech would be about before banning it, and hadn't gone to Police or university constable to see it there were actual threats to safety.
"The speech was not about my views on Hobson's Pledge or race or anything else, it was about my time in politics. It was a historical speech really not defending anybody," he told The AM Show host Duncan Garner on Wednesday.
"It's very clear from her press statement that while she cited security reasons as the reason for the ban, most of the press statement was about my alleged hate speech because I oppose separate Māori wards."
Even Prime Minister Jacinda Ardern has called out Massey University's cancellation as an overreaction.
"If he is asking me for a personal opinion, the example I think he is pointing to I would characterise as an overreaction on the part of the institution," Ms Ardern said during Tuesday's Question Time.
However appearing on RadioLIVE on Tuesday, Prof Thomas refused to apologise for her actions, saying Dr Brash's views on the Treaty of Waitangi are incompatible with Massey, which is now "Te Tiriti o Waitangi-led".
But Mr Brash says he's glad for the widespread support he's received - and he won't take legal action against Prof Thomas.
"I feel very optimistic about the country and the range of people who've said this is a wrong ban has been fantastic," he says.
"I think she almost certainly is feeling bad about herself this morning. I don't want to rub salt in the wound."