National MP Chris Bishop is considering pulling out of his speech at Massey University in protest over its decision to block Don Brash from speaking there.

Photo: RNZ / Richard Tindiller

Dr Brash, a former National leader and Reserve Bank governor, was due to speak to the university's Politics Society in Palmerston North today, but vice-chancellor Jan Thomas cancelled the event citing safety concerns.

Prof Thomas said the decision came at a time of heightened tension over free speech and hate speech prompted by the visit of Canadian alt-right speakers Lauren Southern and Stefan Molyneux to New Zealand.

Mr Bishop, who's due to make a speech to the same Palmerston North club next week, has written to Prof Thomas to complain, calling on her to immediately reverse the "appalling decision".

"It is highly likely to be unlawful and certainly outrageous," he said on Twitter.

I am due to speak to the Massey Politics Club next Wednesday. I have just sent this letter to @ProfJanThomas the @MasseyUni VC. She must immediately reverse her appalling decision banning Don Brash from speaking. It is highly likely to be unlawful and certainly outrageous. pic.twitter.com/DQZiqhzoDg — Christopher Bishop (@cjsbishop) August 7, 2018

The letter said universities were traditionally regarded as "bastions of free speech and critical thought".

"I have no real desire to speak at a university that prefers to preference the views of a tiny, angry minority who wish to shut down speech they disagree with rather than stand up for academic freedom, critical thought, and the values of pluralism and liberal democracy."

Mr Bishop said he was loath to cancel his speech and was waiting to hear Ms Thomas' response.

"The answer to speech that you don't like is more speech - and so it would be a bit strange to cancel my speech on those grounds. But that's something I'm considering."

ACT Party leader David Seymour yesterday called for Ms Thomas to stand down over her decision, while Prime Minister Jacinda Ardern called it an "overreaction".

Mr Bishop said calling for a resignation might be "a step far", but he hoped Ms Ardern and Education Minister Chris Hipkins would take a closer look.

"Universites are specified in the Education Act as having a special role as critics and consciences of society. They're meant to be the place where free thought and expression flourishes.

"In this case, the vice-chancellor, initially on a whim, because she doesn't like Don Brash, has stifled his speech and also the rights of Massey politics club students to hear his speech."

Dr Brash has said he believed it was his views, rather than safety concerns, that led to him being banned from the publicly-funded university.

"I'm stunned that the vice-chancellor of the university - a taxpayer-funded university in New Zealand - would ban my appearing because one or two, presumably thugs, would threaten to cause some kind of mayhem if I turn up."

In her statement yesterday, Prof Thomas referred to Mr Brash's support for the group Hobson's Pledge, which opposes separate electoral wards for Māori.

She also cited his call to allow Ms Southern and Mr Molyneux to speak in New Zealand.