A Greens motion urging MPs to gauge community support for gay marriage has been passed by the House of Representatives.

The motion, which has ignited debate over the issue this week, was passed by 73 votes to 72 with the support of Labor and crossbench MPs Tony Windsor, Rob Oakeshott and Andrew Wilkie.

The Coalition refused to support the motion as did independent MP Bob Katter.

Mr Bandt says the Parliament has made a significant move towards recognising gay couples.

"This is an important step towards reforming the law," he said.

Greens Senator Sarah Hanson-Young has already introduced same-sex marriage legislation into the Senate and has urged the major parties to allow for proper debate on the bill.

"Tony Abbott and Julia Gillard need to stop blocking progressing on this issue," she said.

Earlier this week Labor agreed to back the motion, put forward by Greens MP Adam Bandt, as tensions erupted internally over the party's refusal to allow gay marriage.

Senior frontbencher Mark Arbib was forced to deny he had been sternly rebuked by his colleagues for publicly urging a change in Labor policy.

Senator Arbib said he and other MPs would be pushing for Labor to support gay marriage at its next national conference, which has now been brought forward from 2012 to late next year.

Yesterday Prime Minister Julia Gillard remained steadfast in her opposition to gay marriage and a conscience vote on the issue but said she expected it would be heavily debated at the national conference.

Earlier today, Speaker Harry Jenkins was forced to use his casting vote for the first time in the new Parliament.

The House of Representatives was deadlocked on 72 votes each side during a division on the order of parliamentary business.

Mr Jenkins sided with the Government in the vote, citing precedent.

According to House records, the last tied vote was in April 1992.