Define marriage bill first, says senator

Proposed legislation to legalise same-sex marriage should be drafted and made public before a plebiscite on the issue, Nationals Senator Matt Canavan says.

The Queensland MP says he has concerns about the current proposal, put forward by his colleague Warren Entsch, because it fails to protect freedom of religion and belief.

"They are fundamental rights. I think it's only fair that we tell the Australian people exactly what is envisaged to change if a 'yes' vote succeeds," he told Sky News on Saturday.

"I am deeply uncomfortable about outsourcing the fundamental rights of people, including their freedom of religion, to some kind of tyranny of the majority."