In another sign of the internal ructions over section 18C of the Racial Discrimination Act, Mr Christensen said failure to repeal or at least amend the law would betray the values of the Coalition and amount to a "fundamental breach of faith with our base".

It came as Labor senator Sam Dastyari delivered an expletive-laden tirade on the matter at a university event, accusing "white rich men" and "f---ers [with] their own TV shows" of complaining that the law won't let them be sufficiently racist.

Mr Christensen made a pointed criticism of Treasurer Scott Morrison's remarks this week that amending section 18C would "not create one job", as well as Mr Joyce's comments that people in north Queensland did not invite him into their sheds to talk about race laws.

"I have heard it stated that 'this issue doesn't create one job'. Neither does the Omnibus Savings and Child Care Reform Bill, but we're still doing that," Mr Christensen said in a statement on Thursday.

"I have also heard it said that it's not the issue people are talking about in pubs or in farm sheds. They weren't talking about the Australian Building and Construction Commission either, but we still brought it back."

Mr Christensen, who this week resigned as Nationals whip so that he could speak more freely on party policy, went on to say that section 18C "stifles" free speech in Australia and represented "political correctness enshrined into law".

The controversial section makes it unlawful to offend, insult, intimidate or humiliate another person on the basis of their race. Many Coalition MPs are pushing for the clause to be scrapped or replaced with stricter wording such as "harass" or "vilify".

"Nothing could be more of an affront to Australian values," Mr Christensen said of the law. "And nothing could be more at odds with National and Liberal Party values."

He said the repeal of section 18C was "definitely" a subject of discussion at local party branches and state conventions.

"It's an issue of great importance for the people who fundraise for us, who hand out how-to-vote cards for us and who pre-select us so that we can stand as candidates and serve our electorates," he said.

"As far as I'm concerned this is a fundamental issue not only for democracy, but for the base of the Liberal and National Parties. I would expect that those parties who form the Coalition would not walk away from it.

"We should repeal, or at the very least amend, section 18C of the Racial Discrimination Act sooner rather than later. Failure to do so will represent a fundamental breach of faith with our base."

Mr Joyce said he got along well with Mr Christensen but would focus on the big issue for his electorate of Dawson, which was the dispute between sugar giant Wilmar and local cane growers.

"That's the big one, that's what I'll be concentrating on," he said. Section 18c could be dealt with "down the track", he said.

Meanwhile, in an expletive-laden performance at a Sydney University Labor event on Wednesday night, Senator Dastyari attacked Turnbull government MPs for focusing their concerns on section 18C rather than on workers set to lose penalty rates.

"Things are just getting f**king crazy at the moment in Canberra," he said.

"In the same week where 700,000 people are potentially losing their penalty rates, the only thing the conservatives seem obsessed about is how they can be a bit more racist.

"They've gone off on these bizarre, strange tangents ??? that actually mean nothing to anyone out there. The right in this country has become radicalised. It's frightening stuff."

The case to change 18C was being promulgated by "a bunch of white rich men complaining about the fact that they feel that their voices have been silenced," Senator Dastyari said.

"Most of these f**kers have their own TV shows," he said in an apparent reference to Sky News. "And all they do is go on about 'oh, my freedom of speech'."