The Massey University corporate communications director told Newshub the comments were "enough red flags to tip the balance" in the eyes of vice chancellor Jan Thomas.
However, Thomas scrapped the event over security concerns yesterday, citing the welfare of students as her main concern.
"It was a really tough decision, I don't like making these sorts of decisions, but it was for the good of the community," she told Larry Williams on Newstalk ZB.
Brash was upset over the decision to bar him from attending the university and believes Thomas was motivated by controversial comments he's made in the past.
No stranger to controversy, Brash made headlines with his infamous Orewa speech in 2004 when he was the leader of the National Party.
In it he criticised "separatist" policies such as the allocation of Māori electorate seats in Parliament and the use of Māori spiritual traditions in official events.
Brash told Larry Williams yesterday he was simply attending to talk about his time as National Party leader and nothing else.
"The irony is, I was to speak about my time as National Party leader between 2003 and 2006, I wasn't talking about current events at all.
"In my speech notes, I make no reference to the Canadians or to the Hobson speech or anything else," he said.