Coalition member Jordan Williams told the Herald that during a conference yesterday it was agreed unanimously to issue proceedings against the vice chancellor.
"We are going to need a little bit more money in the pot to do it, but we are very confident we will get there."
To label Brash as espousing hate speech, when in the past he had been the leader of opposition and just shy of becoming Prime Minister, was a "dangerously low" bar to set, Williams said.
"In a free society we need to protect the expression of ideas, even if we disagree with them," he said.
"You can't defend free speech by only defending views you like - because that isn't free speech."
Fellow Free Speech Coalition member Melissa Derby said the university's action in barring Brash raised very similar legal and ethical issues as the Auckland Council's ban on Southern and Molyneux from Council-owned venues.
"In both bases, an authority has used threats of disruptive protest as an excuse to shut down contentious speech. This is the thug's veto in action," she said.
The "security concerns" appeared to be a ruse to obscure the vice chancellor's motivation – a personal distaste for Brash's opposition to Māori wards on councils, in addition to his support of the speech rights of the recent Canadian visitors, she said.
On Tuesday, Thomas told the Herald the decision to cancel the speech came after the Politics Society raised concerns about their ability to meet the conditions agreed to as a result of a surge in interest on social media.
Thomas issued a statement that said the talk was cancelled due to security concerns.
The statement said Thomas supported free speech on campus but totally opposed hate speech.
"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," the statement read.
"Whether those views would have been repeated to students in the context of a discussion about the National Party may seem unlikely, but I have no way of knowing.
"In my opinion the views expressed by members of Hobson's Pledge come dangerously close to hate speech. They are certainly not conducive with the University' strategy of recognising the values of a Tiriti o Waitangi-led organisation."
There was heightened sensitivity and passion at the time, following the protests both against and in support of Southern's and Molyneux's right to be heard, she said.
"Our ultimate responsibility is for the safety and wellbeing of students, staff and members of the public on our campuses and under those circumstances cancelling the booking is the right thing to do," she said.
"The members of the Politics Club have acted responsibly in raising their concerns with the University and are free to meet Dr Brash at another venue if they wish."