Two pieces of legislation aiming to legalise same-sex marriage will be presented to federal parliament next week.
Labor backbencher Stephen Jones will table his private member's bill on Monday, while a second will be jointly sponsored by Greens MP Adam Bandt and Tasmanian independent MP Andrew Wilkie.
Both are likely to include protections for churches that refuse on religious grounds to marry same-sex couples.
Mr Bandt wants both bills referred to a parliamentary inquiry which is considering another piece of Greens legislation on the same issue.
While he and Mr Wilkie were moving early on the matter, Mr Bandt cautioned the best approach to get the laws through would be to take time and make it a cooperative multi-party effort.
He wants all MPs to vote according to their conscience. Labor MPs have been given a free vote on the issue, but not those in the coalition.
The Greens deny trying to usurp Labor efforts.
Mr Bandt said he tried to meet Mr Jones on Thursday morning to discuss cooperating on the issue but the Labor MP had cancelled.
'I would be quite happy to talk about co-sponsorship, indeed that's been our invitation from the beginning,' he told reporters in Canberra.
'I just want to make sure that we see reform in this area and that we don't see grandstanding.'
Referring the two bills to a Senate inquiry would mean the best of all the pieces of legislation on offer could be put to a vote, Mr Bandt said.
Mr Wilkie reminded Opposition Leader Tony Abbott that Liberal party policy was to allow conscience votes on all matters.
'It is only really a significant issue for members of the opposition frontbench,' he told reporters.
'It should not be any issue at all, as far as the party rules go, for a Liberal backbencher to vote in support of marriage equality.'
Mr Abbott was attempting to coerce his MPs because he saw a political benefit in doing so, Mr Bandt said.
Comment was being sought from Mr Jones.
