This was despite Mallee being one of the electorates most opposed to same-sex marriage in Australia.

A Monash University and University of Melbourne study of responses from almost 650,000 voters in the previous federal election campaign has estimated the national support for same-sex marriage.

Mallee was the thirteenth-most opposed out of 150 electorates, with an estimated 45 per cent of voters declining to support changing the definition of marriage to include gay and lesbian couples.

That is still a minority, and if the study is accurate it would see Mallee voters ultimately back a plebiscite to legalise gay marriage.

Member for Mallee Andrew Broad has pledged to vote for or against gay marriage based on the plebiscite result in his electorate, as opposed to the nation as a whole.

That is, if the legislation to enable a $160-million plebiscite in February 2017 ever passes the senate.

The Greens have vowed to vote against holding a plebiscite and Labor and the Coalition failed to come to an agreement this week.

Mr Broad said he was not sure about the accuracy of the study’s results.

“They did their research on data that came through from the ABC Vote Compass, and divided that by electorates,” he said.

“That’s an indicative form, I’m not sure it’s the most accurate form.

“But it actually leads into why don’t we have a plebiscite? What’s to be scared of? The quickest way to resolve this issue, either in the negative or the positive, is via a plebiscite.” 

The same study estimated that less than 40 per cent of voters in Wannon were opposed to legalising same-sex marriage.

Member for Wannon Dan Tehan has pledged to follow the national result if a plebiscite is held.