Canning MP Andrew Hastie has confirmed he will abstain from voting on same-sex marriage legislation after a survey of his electorate voted in favour of the changes.

Mr Hastie said he recognised the yes campaign had won a cultural and legal mandate for the change in law, but that abstaining from the vote would respect the outcome of the postal survey, allow him to exercise his freedom of conscience and give a voice to the 40 per cent of his electorate who voted no.

Liberal MP Andrew Hastie will abstain from voting on same-sex marriage legislation. Credit:Richard Polden

The Canning electorate, which includes Mandurah, Pinjarra, Dwellingup and the Peel region, returned 60.2 per cent support for the change in the survey.

Mr Hastie said he had been open about his intention to abstain from a parliamentary vote even if his electorate supported same-sex marriage.