Malcolm Turnbull has declined to confirm reports he gave a Senate crossbencher an indication of his general support for changes to racial hate-speech laws.

The prime minister, soon after taking the job in September last year, told Family First's Bob Day that he would look at the matter early in 2016 after asking the senator to delay a vote on his private bill, The Australian reported on Friday.

When quizzed about his position on the need to change Section 18C of the Racial Discrimination Act, Mr Turnbull told Neil Mitchell on 3AW radio: "It depends how you amend it."

Momentum is gathering inside the government for a change to Section 18C which makes it illegal to offend, insult, humiliate or intimidate someone because of their race.

Liberal backbencher Cory Bernardi plans to introduce a bill in the first week of the new parliament that seeks to remove the words "offend" and "insult" from the act.

Coalition supporters of the change believe they are within one or two votes of securing a Senate majority on the issue.

But Mr Turnbull insists changing the act is not a priority for the government.

"My job is to keep an eye on the key objectives," he said.

Senator Day revealed to The Australian that Mr Turnbull had phoned him last year during debate on his bill and the two "agreed the time (for a vote) was not right for either of us at that time".

Mr Turnbull indicated his "general support" for the push to amend the contentious section, he said.

"We landed at the position where I would not put it to a vote, but would bring it back in the new year and we agreed with that timetable," Senator Day said.

Liberal Democrats senator David Leyonhjelm, who was a co-sponsor of the bill, said a vote last October would have "killed the bill", but he had not welcomed Mr Turnbull's intervention.

"Bob told me that the prime minister had called him and asked him not to bring it on," he said.

"My answer was to tell the prime minister to get stuffed, to bring it on anyway, but Bob is an obliging sort of a bloke and supportive of the Libs and he had made up his mind he would hold back."