The Turnbull cabinet has instructed Philip Ruddock, a former Liberal minister and the current mayor of Hornsby, to examine whether current Australian law does enough to protect religious freedoms.
A statement from the prime minister’s office said Mr Ruddock would conduct a "timely expert stocktake" that would determine whether there was any need to change the law to enshrine religious freedoms.
The announcement comes amid pressure from Coalition conservatives who want to see religious exemptions built into the bill to legalise same-sex marriage.
Mr Ruddock is due to report back by March 31 next year, throwing the broader debate on religious protections beyond the government's self-imposed Christmas deadline to legalise same-sex marriage.
But Treasurer Scott Morrison welcomed the review but said it "[did] not replace" the need to build religious exemptions into Senator Dean Smith's bill to change the Marriage Act.
"Any reforms to protect religious freedom at large should be undertaken carefully. There is a high risk of unintended consequences when Parliament attempts to legislate protections for basic rights and freedoms, such as freedom of religion," Mr Turnbull said in the statement.
"The government is particularly concerned to prevent uncertainties caused by generally worded Bill of Rights-style declarations."
Mr Ruddock said he would bring a "considered view" and stressed the quality of his contacts in various religious communities.
"I certainly know a lot of the Christian leadership, I know many in the Islamic community, I'm very much focused on the Hindus and the Buddhists," Mr Ruddock told Channel Nine.
Coalition ministers have been divided on the question of whether to incorporate religious protections into the same-sex marriage bill, or to pass the reform swiftly and then move on a separate religious freedoms bill in 2018.
Immigration Minister Peter Dutton and Finance Minister Mathias Cormann, both considered conservatives, have suggested many religious protection issues could be dealt with in a separate bill next year.
Attorney-General George Brandis has suggested several amendments to Senator Smith's bill to legalise same-sex marriage, including extending the right to refuse to officiate same-sex weddings to objecting civil marriage celebrants.
He also suggested importing some of an international human rights treaty to protect the right to "freedom of thought, conscience and religion".
Liberal MP Tim Wilson, who supports same-sex marriage, said a stand-alone Bill of Rights was inconsistent with socially conservative values.
"It's an oddity to see many people who identify as conservative or socially conservative, who have traditionally opposed a Bill of Rights or Charter of Rights, now prosecuting this cause," Mr Wilson told the ABC's Insiders on Sunday.
Mr Ruddock will share the advisory panel with Human Rights Commission president Rosalind Croucher, academic and former judge Annabelle Bennett and Jesuit priest Frank Brennan.