A key plank to NZ's democratic society is the right to free speech, but the Auckland Council is going against that principle by banning a visiting Lauren Southern and Stefan Molyneux from speaking at council venues.

Mayor Phil Goff says the couple won't be permitted to preach their far right, anti-Muslimism rhetoric.

Leading Māori academic Ella Henry says she backs the council's stance.

"That does not mean they cannot come to New Zealand or they can't speak in New Zealand. It simply means that we of Auckland stand behind our mayor and say that our buildings are not available for people who, some have accused of speaking hate speech."

Both Southern and Molyneux are known for their polarising views on topics including feminism, gender, immigration and Islam.

Goff told TVNZ's Q+A that he must protect those groups.

"I've got an obligation to protect ethnic and religious minorities who are being brought into contempt, who are being abused, provoked and insulted by the sort of language that these people are using."

Henry also says that this issue is kind of similar to the article Sir Bob Jones wrote that offended film-maker Renae Maihi, who then ran a petition.

"She believed he was engaging in hate speech and interestingly he has since threatened to sue her, she started a campaign and received huge support from the public."

In the end, Henry says it's an important topic to talk about.

"I think that the fact that we're having this debate about what is hate speech and whether or not there is freedom of speech is a really important conversation for any lively democracy to be having."