Barnaby Joyce has broken with cabinet solidarity to blast the Liberal Party for catering to its fringe "extremities" and proposing to water down Australia's race hate laws.

The Deputy Prime Minister and Nationals leader was part of Monday's cabinet decision to pursue the change, but said the issue was irrelevant to ordinary voters.

Mr Joyce told Fairfax Media that while he had some sympathy for the underlying argument in favour of change, the government had harmed itself on the matter, and handed Labor a political weapon to attack the Coalition government.

The proposed change has fervent support among the libertarian faction of the Liberal Party but frustrated the Nationals: "Deal with it and move on," a frustrated Mr Joyce urged his coalition partner.

The proposed changes to the wording of the act were introduced to the Senate on Wednesday and have triggered a storm of protest from ethnic and community groups.

However, it is likely to fail in the face of opposition from Labor, the Greens and the Xenophon team.

He also appeared to contradict Prime Minister Malcolm Turnbull, who on Tuesday argued the changes to section 18C of the Racial Discrimination Act would "strengthen the protection of Australians from racial vilification".

Mr Joyce said: "There is a sense that the world is too politically correct" and that "if this engenders a greater freedom of speech and is more robust than the initial 18C, that's a good thing, because otherwise you become too wrapped in cotton wool."

The changes announced on Tuesday would see legal prohibitions on people's right to "offend, insult or humiliate" removed from section 18C, instead making it illegal to "harass" or "intimidate" a person. Changes to speed up the Human Rights Commission's handling complaints will also be made.

Mr Joyce's blunt intervention in the debate comes a day after he told the Coalition party room that changing 18C was a political distraction.

"This is an issue that if you have to deal with it, deal with it, but deal with it and move on. It is definitely not the issue people are talking about in the beer garden on Friday night or at the counters of banks, or to be quite frank, in the big office blocks when they finish work on Friday night," he said.

"What they are talking about is 'what on Earth is happening to my power prices'. They want a job.

"This is an issue, it is an issue but I'll be frank, it lives in the extremities of the bell curve. Where do you meet those people [who care about 18C]? At party meetings, they are absolutely blessed people and they are terribly politically involved and they have an intense interest in some of the minutiae of debate. They come into your office to rant and rave about it, all four of them."

The Deputy Prime Minister said people were more concerned about rising prices, and about whether the government was building dams and sealing roads.

In an apparent admission that debate over 18C and same-sex marriage had distracted from the Coalition's agenda, Mr Joyce said the Turnbull government should not engage Labor in these philosophical debates.

"Governments deliver on practical outcomes, oppositions talk about things that are philosophical ... it's a tactic of the opposition to take you to where they have equal potency – where do they have equal potency? On general philosophical debates," he said.

"Only governments deliver. We should be talking about things where we have greater potency than the opposition, which is delivery. Power prices, dams, sealing roads. Things that I can show and touch."

One of the key concerns with the proposed legislation is the definition of "harass" and whether it might make it more difficult to make complaints against race-hate speech.

Social Services Minister Christian Porter said the difference was "a measure of what is done to a person".

"It can be seen, it can be heard, it can be witnessed and it can be objectively measured," he said.

"Now the difficulty is with that formulation of words – 'offend, insult, humiliate' – which many submissions to the recent enquiry noted, invariably involves a subjective element."

But the definition of "harass" is also considered vague, and has left the government open to having to explain how many insults constitute harassment.

Mr Turnbull told the Parliament the bill "specifically states that a single act" is enough to meet the definition.