Mr Dutton's comments come just days after the UN special rapporteur warned politicians  were "taking advantage of the populist vote", making protections such as 18C more important than ever.

Mr Dutton said Ms Triggs "has a lot to answer for" over the commission's handling of racial discrimination complaints, including a complaint, since withdrawn, over Mr Leak's  cartoon depicting an Indigenous father holding a beer can asking a police officer his son's name.

In defending Mr Leak Mr Dutton described the situation as "absolutely ridiculous" and impinging on free speech.

"The policy at the moment as it operates that would allow Bill Leak to get into the trouble that he has is evidence enough that it needs to be looked at," he told Sky News.

Ms Triggs' appointment with the commission will not be renewed when her contract expires next year, but she herself has indicated support for proposals to change section 18C, which would remove "insult and offend" and insert "vilify" in their place.

But in a sidenote to his 18-day visit to Australia examining its treatment of asylum seekers and refugees, UN special rapporteur Francois Crepeau made mention of the importance of maintaining section 18C, which makes it illegal to offend or insult on the basis of race.

Earlier this month, Prime Minister Malcolm Turnbull, who previously had declared it not a priority, announced an inquiry into the act, to determine its impact on free speech and whether changes were needed.

At the end of his Australian trip, Mr Crepeau made note of 'xenophobic speech and acts' across the world and said "language matters", with one in five Australians having experienced race-hate speech and with one in 20 having been physically attacked because of race.

He said politicians had tapped into the "negative discourse" as a vote winner which "seems to have given permission to many to act in xenophobic ways and allow for the rise of nationalist populist voices".

Mr Crepeau said calm, "serene" reasoned voices were needed to combat the trend – as well as robust protections, such as a human rights act, which would allow courts to decide when something went too far.

"In all countries in the world we have seen in the past years politicians taking advantage of the populist vote and deciding that it was in their political advantage to use immigration as an election tool," he said.

"This has existed everywhere, not simply in Australia- everywhere - and it is for me a regret to see that this has translated in acts of violence against migrants, in xenophobic attitudes, in insults, in creating a much more intense vilification of certain categories of migrants and refugees.

"This has not escaped the political stage in Australia, it has not escaped the political stage in my country [Canada], or in Europe or North America – this has been something general.

"It is very important, and I repeat the importance of a human rights framework and of oversight mechanisms, it is very important that we have serene, reasonable institutional that will come down on this kind of speech and acts of violence, saying it is collectively unacceptable.

"And we need to have these mechanisms in place – human rights commissions, equality commissioners and all tribunals – these are checks and balances that will  allow a reasonable voice inside the political debate, saying – 'you can not say this about this group – there are many things you can say about this group, but not this'.

"…And this is something that the court will be able to interpret."

Mr Crepeau said the issue of interpretation of the law should be left to the judges.

"To me, what is sort of missing here…what is missing in Australia is this global human rights framework, at the constitutional level or legislative level, where we have a comprehensive human rights framework, where judges would be empowered at balancing the rights – you know, you have the right of freedom of expression, but you also have a right to privacy and also the right of – such laws such as libel and others that intervene in the interpretation of the right of freedom of expression," he said.

"And I think having a comprehensive human rights framework where judges would be empowered, would reduce considerably, the sensitivity of debates."

The Parliamentary Joint Committee on Human Rights will report back on whether sections 18C and 18D need reforming by February 28 next year.