The Facebook comments that convinced Massey University to cancel an event at which Don Brash was due to speak have been revealed.

The former National Party leader and founder of treaty lobby group Hobson's Pledge was invited to speak at Massey's Manawatu campus on Wednesday as part of a series of political talks.

On Tuesday, Vice Chancellor Jan Thomas called off the event because of what she called "security concerns" - a move which has since been criticised by politicians including Chris Hipkins, Paula Bennett and Prime Minister Jacinda Ardern.

"I made the decision - it was not an easy decision at all - based on my concern for potential violence on our campus," she told RadioLIVE hosts Ryan Bridge and Christine Rankin.

Vice Chancellor Thomas mentioned seeing threatening comments about the event on social media, although declined to go into specifics other than saying one person had mentioned bringing a gun to campus.

Newshub has learned that two specific Facebook comments prompted the cancellation.

One was a post on August 3 by a Palmerston North man believed to be a member of the Stormtroopers gang. He posted a link to the event page with the caption, "This guy lol...if your [sic] up to nothing wensday [sic] head up to massey uni," accompanied by a laughing emoji and a red circle with a cross through it.