National Party Leader Simon Bridges says Phil Goff is "entitled" to ban far-right Canadian activists Lauren Southern and Stefan Molyneux from speaking at council venues.
Ms Southern is a 23-year-old author and her views have been described as anti-Islam, anti-refugee, anti-feminist and borderline white nationalist.
Mr Molyneux is also an author and YouTuber, and he usually covers topics like multiculturalism, anti-feminism and anarcho-capitalism.
The pair were due to speak at the Bruce Mason Theatre in August as part of an Australasian tour, but Mr Goff on Friday said he would not allow any Auckland Council venue to be used by them, and they then cancelled their visit to New Zealand.
"[Auckland Council] venues shouldn't be used to stir up ethnic or religious tensions ... views that divide rather than unite are repugnant and I have made my views on this very clear.
"The right to free speech does not mean the right to be provided with an [Auckland Concil] platform for that speech."
Both the UK and Australia have declined visa for Ms Southern, with the UK saying her presence was "not conducive to the public good".
Ms Southern responded to Mr Goff's decision by Tweeting: "Hey friends in New Zealand ~ looks like you've got a free speech issue there!
"No system will survive if it is contingent on shutting down any discussion or criticism of its issues ... what kind of faith does this inspire in your ideology if it cannot be questioned? Does the "enrichment" of diversity come at the cost of our rights to speech?"
Mr Bridges, speaking this morning to TVNZ 1's Breakfast programme, said Mr Goff was "entitled" to ban them from the venues, but that banning them from entering New Zealand would be too far.
"I disagree strongly with what these activists are saying but I think it's a dangerous thing to say "because we don't like what you're saying we won't let you in," Mr Bridges said.
"I can see how he's made his decision, but I wouldn't have banned them from coming to New Zealand.
"I think we should allow people we strongly disagree with to come - we're a mature, liberal democracy."
The pair were technically not banned from coming to New Zealand, but were not granted automatic visas due to being denied entry to the United Kingdom previously.
Under New Zealand's Human Rights Act, it is illegal to incite hostility against any group based on their race - to "bring into contempt or ridicule, any such group of persons in New Zealand on the ground of the colour, race, or ethnic or national origins of that group of persons".
However, this is tempered by the Bill of Rights Act, which guarantees freedom of expression: "everyone has the right to freedom of expression, including the right to seek, receive, and impart information and opinions of any kind in any form".