Independent federal MP Tony Windsor says he'll support a Greens motion that, if passed, would require members to canvass their electorates' views on gay marriage.
Mr Windsor said on Tuesday he'd support Labor in backing the call for "all parliamentarians to gauge their constituents' views on ways to achieve equal treatment for same sex couples, including marriage".
With the coalition vowing to vote against the motion later this week, the votes of the five independent MPs will be crucial.
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Queensland's Bob Katter has already declared he'll side with the opposition. He says he knows what voters in his electorate of Kennedy think.
"Their attitude is not in favour," Mr Katter told reporters in Canberra.
But Mr Windsor says he's happy to ask people in New England what they think about gay marriage.
"I agree with the amendment that was put up last night," he told ABC TV.
"I'll be consulting with my constituents as to what they think and I'll be representing their view."
Asked for his own personal view on same-sex marriage, Mr Windsor said: "Well, I married a woman."
But he went on to say he didn't have a problem with it "as long as it's not compulsory".
"I'm very happy with my wife," he said.
