Questions over the power of university leaders to veto speakers.

Hobson's Pledge founder and former National party leader Don Brash has been uninvited from a students politics club at Massey University's Manawatu campus.

Vice-Chancellor Professor Jan Thomas says the decision to cancel was made after online threats against the event.

But Free Speech Coalition spokesperson Dr David Cumin told Kate Hawkesby he doesn't buy that.

"When she freely admits the security on campus were contacted and didn't advise shutting it down then I think there are large questions to be raised about how much power she has to decide on who can and can't speak"

Cumin says he is concerned as this comes on the heels of the Southern/Molyneux cancellations.

The Canadian pair were prevented from speaking in Auckland Council venues because of concerns over unrest.

"We have like what seems like another threat to free speech and free expression coming from thugs within society who want to shut it down with violence and that seems like a real concern."

LISTEN ABOVE AS DAVID CUMIN TALKS TO KATE HAWKESBY