More Australians are in favour of changing the Racial Discrimination Act, new polling to be given to a parliamentary inquiry shows.

A survey of 1000 people by Galaxy Research, for the Institute of Public Affairs, shows 48 per cent approve of calls to remove the words "insult' and "offend" from section 18C - a rise of three points.

"Much to the surprise of some members of the media and the political class, free speech matters," IPA director of policy Simon Breheny told The Australian, ahead of its appearance before the inquiry into free speech on Tuesday.

Prime Minister Malcolm Turnbull last year asked the human rights committee to look into the Act.

Committee chair Liberal MP Ian Goodenough believes resources need to be directed at stopping racial discrimination and serious conduct which results in harm, violence or incitement to violent acts and "not cartoons and trivial matters".

"What we are trying to achieve is to protect ethnic and racial groups from harm and detriment but it is not the role of government to police petty social misdemeanours," he told the paper.

Mr Goodenough said as a migrant of Eurasian heritage he sees the need to protect ethnic and racial minorities, but at the same time protect mainstream Australians from situations of reverse discrimination.

More than 11,000 written submissions have been received by the committee.

Deputy Labor leader Tanya Plibersek said jobs, health and education were the main issues for Australians, not this debate.

"Being able to insult and offend people on the basis of race is not a mainstream issue," she told ABC radio.

"People should think a little bit about the protections that 18C affords to free speech and relax a little bit."