Don Brash was barred from speaking at Massey University after Vice-Chancellor Jan Thomas cited security concerns, but documents requested under the Official Information Act reveal a different story.

Brash was due to give a speech to the University's Politics Society in August, speaking about his life in politics, but after a threat to security, the university canned the talk.

The controversial decision by Massey University added fuel to the free speech debate in New Zealand.

In an Official Information Act request, by right-wing blogger David Farrar, documents show that security was not the main concern, but Thomas saying she didn't want a "te tiriti led university be seen to be endorsing racist behaviours".

An email was sent on July 9 in response to Thomas' assistant after she advised Thomas she was not free to attend the debate as an observer.

"Ok however Donald Brash was v [very] racist re [regarding] Maori and Maori seat.

"Can you in the first instance see what [Name omitted] and [Name omitted] think about this and what we can do to manage, minimise etc," Thomas said in the internal email.

On July 10, she sends another email saying the subject was on her mind.

"I would like to know what are our options re [regarding] not allowing politics clubs to hold event on campus - free to hold any event but not with any inference of support by university.

"Will hit the fan in the media if we go this way. However, racist behaviour of Brash - given te reo is a official language of NZ and we are a tiriti led university - can't be ignored

"If goes ahead could be on the condition that Brash and others agree to respect the values of the university etc etc? But would be good if we can cut off at pass some how," Thomas said

Then on July 11, Thomas receives an email from a staff member saying there was no criteria in the university policy regarding what the university would or would not approve.

"The ground for me declining it may well be challenged and as per [name omitted] email yesterday I think would present a very real risk of us being accused restricting free speech etc," the staff member said.

The vice-chancellor then replied, saying she was still "deeply concerned" about the matter asking if there was any mechanism the university could use to stop the event.

"Do we have any mechanisms that might be able to be used here? The financial agreements with clubs and societies and associations? Use if facilities policy? How do the Māori community feel about this might be good to know too? What is the politics club schedule.

"Agree is a PR [public relations] problem in all circumstances. But being tiriti led will have huge challenges for us if we are to be brave enough to be authentic."

The next piece of correspondence is an email sent to Thomas where a staffer says Brash uses "free speech as a shield which to hide, as do many colonial racists and conservative commentators".

Then on July 13, another email from Thomas reveals Brash speaking still was of great concern to her.

"So I sum, I really want to find a way to indicate that Brash is not welcome on campus unless he agrees to abide by our values and the laws against hate speech. He is not a sitting politician so what is he getting this airing."

It wasn't until August 7, the day before Brash was marked to speak at the Manawatū campus that Thomas cancelled the speaking event citing security concerns.

In a statement, Massey University said it cancelled a booking made by a students' politics club. It referenced Brash as a former politician and Hobson's Pledge founder, as well as a supporter of controversial Canadian speakers Lauren Southern and Stefan Molyneux.

Prime Minister Jacinda Arden weighed in on the Brash and Massey University conflict, stating that it was an "overreaction on the part of the university".

"There'll be a number of examples over the years where politicians and ex-politicians have gone on to campuses and there has been a bit of a stir around their views and people using their voice to either protest or support," she said.

Brash later spoke at a debate over free speech at University of Auckland.

There, he joined Herald reporters Simon Wilson and Fran O'Sullivan, New Conservative party deputy leader Elliot Ikilei and former Governor-General Sir Anand Satyanand.