A split has emerged inside the Human Rights Commission over the latest move to amend section 18C of the Racial Discrimination Act, with Race Discrimination Commissioner Tim Soutphommasane not on board with a proposal backed by commission president Gillian Triggs.

Professor Triggs said the independent body would consider recommendations made by the parliamentary inquiry into free speech, announced on Tuesday, and said a proposal to to remove "offend" and "insult" from the law, replacing them with "vilify", would amount to a strengthening and "could be a very useful thing to do".

Mr Soutphommasane said he would contribute to the inquiry as a matter of course but that it "remains my view that there is no case for changing section 18C of the act".

"Our society must have strong protections against racial abuse and vilification, while guaranteeing freedom of speech," he wrote on his blog.