The Greens will use Phillip Ruddock's review of religious freedoms to build momentum for an Australian bill of rights and with Labor's support it could be put before a Senate inquiry as early as next year.

The Coalition, the Greens and the Opposition will clash over religious freedoms when Parliament resumes in February after Treasurer Scott Morrison vowed to defend Christianity from discrimination following the passing of same-sex marriage legislation.

Mr Morrison fired the first shots in the post same-sex marriage debate by declaring he would "call out" offensive remarks against religion and attacked Greens Senator Nick McKim for puportedly advocating for non-denominational celebrations at Christmas.

Senator McKim believes a charter or bill of rights could satisfy both religious conservatives and advocates for greater social freedoms.

Senator Nick McKim Peter Mathew

"Religious rights are important rights but they need to be protected in a way that balances other rights," he said.

"There is a difference between the right to believe in religion and the right to practise by discriminating against other people."

Some conservative Christians have voiced concerns about bakers being forced to bake cakes for same-sex marriages but there are still no public examples of businesses refusing services to same-sex couples.

A bill of rights modelled on international examples in the US, Canada and the UK, would give legal protection to Australians who feel they are being discriminated against, regardless of their background.

Hornsby Mayor and former federal minister Phillip Ruddock has been appointed to conduct a review into religious freedom. Nick Moir

At present, Australia only has five explicit individual rights contained in the constitution, the right to vote, protection against acquisition of property on unjust terms, the right to a trial by jury, freedom of religion and prohibition of discrimination on the basis of your state.

It is understood the Greens have been in discussion with Labor about getting the matter put before a Senate inquiry, the first step in assessing the merits of constitutional reform.

Shadow Attorney-General Mark Dreyfus. Fairfax Media

With the support of five crossbenchers it could pass without the government's backing.

Labor's shadow attorney-general Mark Dreyfus left the door open to negotiation next year and said the opposition would decide its position through normal party processes.

Treasurer Scott Morrison Alex Ellinghausen

"The current national platform contains a pledge to keep the national human rights framework under review to ensure it is fit for purpose," he said.

Senator McKim said with the Ruddock review into religious freedoms underway it was now time to have a national discussion.

"We are the only liberal democracy in the world that does not have a bill or charter of rights," he said.

"Ideally, rights would be enshrined in the constitution but that is obviously a long process and one that is difficult unless we have political unanimity."

In November, former Howard government attorney-general Phillip Ruddock was appointed to chair the panel on religious freedoms.

Mr Ruddock, who is now the mayor of Sydney's Hornsby Council, is one of five members on the panel who will meet for the first time in the new year.

One member of the panel, University of Queensland constitutional law professor Nicholas Aroney has argued religious freedom is becoming "at best a second-class right" as "anti-discrimination law is increasingly prioritised".

Professor Aroney, Mr Ruddock and the other panelists including Human Rights Commissioner Rosalind Croucher, Federal Court Judge Annabelle Bennett and Jesuit priest Father Frank Brennan are due to hand down their findings in March.