Growing MP support for gay marriage

Australian Marriage Equality figures show a near-majority support by MPs for legalising same-sex marriage.

Gay marriage advocates believe they are just shy of majority support in parliament's lower house. (AAP)

Same-sex marriage advocates believe they are just four votes shy of majority support in parliament's lower house.

But Australian Marriage Equality figures depend on Liberal MPs being allowed a free vote on the issue.

"Given a cross-party free vote, the reform has a good chance of passing," national director Rodney Croome told Fairfax Media on Wednesday.