Wairarapa MP John Hayes won't reveal his views on gay marriage, claiming his vote on the bill will be based on his constituents' views.
Labour MP Louisa Wall's private member's bill would amend the Marriage Act to define marriage as a union between two people regardless of sex, sexual orientation or gender identity.
Mr Hayes told Wairarapa Times-Age he didn't think his own opinion on gay marriage was relevant and that he would be representing the views of the community in Parliament.
He said he has been researching both marriage and civil unions, and has begun canvassing the opinions of people in the electorate. "I intend to represent what is the majority community opinion ... it's more liberal than anticipated."
Mr Hayes said he has a sense that the community has moved on recent years, and although he had expected the "older element" to be quite conservative he had not found that to be the case.
Mr Hayes was not present in Parliament for the final reading of the Civil Unions Act 2005, but voted for an unsuccessful amendment to the Marriage Act in 2005 which said marriage should be between a man and a woman. The bill is expected to be debated in Parliament at the end of this month.
It will be decided by conscience vote, and will go through a select committee for public consultation if successful at the first reading.