Labor MP won't change gay marriage view

The Labor MP who represents one of the electorates most strongly opposed to same-sex marriage insists he will back the change in parliament.

Tony Burke will back marriage law changes despite 70 per cent of his electorate voting No. (AAP)

Labor frontbencher Tony Burke has no intention of changing his support for same-sex marriage despite nearly 70 per cent of his western Sydney electorate rebuffing his stance.

The Watson electorate recorded one of the highest 'no' votes in the country.

Mr Burke told ABC radio on Thursday that opposing same-sex marriage in parliamentit would be completely inconsistent with his pre-election position and his commitment to address discrimination.

Asked if he was concerned about the response in western Sydney, Prime Minister Malcolm Turnbull said "it is a big country" and people should not lose sight of the overwhelming 'yes' vote.

"You've got in western Sydney, in some parts of western Sydney, you've got very diverse cultural communities," he told Network Seven.

"In some of those seats you've got a very big Muslim community, who are very conservative on issues like this and very little support for same-sex marriage, but that's fine. It's a free country."