ACT Senator Zed Seselja will vote "no" in the Turnbull government's postal plebiscite on same-sex marriage, arguing Christians and other religious believers could persecuted for their views on marriage and sexuality if the law is changed.
A long-time opponent of same-sex couples' right to marry, the Assistant Minister for Social Services and Multicultural Affairs said the voluntary, non-binding vote would give every Australian adult their chance to express their view.
He confirmed he would vote to support changes to the law in Parliament if the results of the plebiscite favour same-sex marriage.
"Obviously there will be a vigorous campaign and I will be voting "no", I'll be voting against changing the Marriage Act," he said.
"I've long been on the record for that. I think some of the issues that have been raised about issues like religious freedom, we've seen in other parts of the world that when we do redefine marriage that religions, Christians and others, can find it difficult.
"They can find there is persecution when they argue their view of marriage and sexuality. We should be protecting those kinds of things.
"Everyone will be able to have their say. What I think will be no more important in this debate than the views of 16 million other Australians."
Senator Seselja told Sky News on Thursday politicians should honour the results of the vote in Parliament.
"I'd call on everyone to honour the will of the Australian people as expressed through this plebiscite, so for those of us who are arguing against change, if it goes against us, we should honour it. That's what I'll do.
"We can talk about opinion polls, a lot of politicians have said 'well the opinion polls show 60 per cent' or some have claimed as high as 70 per cent. If that's the case, that'll be reflected in the plebiscite and of course then it will sail through the Parliament," he said.
"If it's not the case then the Australian people will have - in a much more meaningful way - expressed their view because everyone's going to have the opportunity to do that. I think we should all honour it and I certainly will."
He said there had been "censorship" of people arguing against same-sex marriage.
"Even the ABC, who are tasked with being fair in their charter, haven't actually been fair on this issue and haven't equally given both sides an airing. There's been other networks who have censored ads.
"There's going to be a real responsibility if we're going to have a fair dinkum debate. We shouldn't see those kinds of extreme comments on either end... but certainly media proprietors have a responsibility to be fair, not to campaign for one side.
"Those arguing against change do have a lot of things stacked against them. Virtually every media outlet is campaigning for change, the ABC has been effectively campaigning for change and there's a lot of corporate money that we've seen.
"I expect that we will see the "yes" case outspend the "no" case, probably by 10 to one," Senator Seselja said.
Labor senator Katy Gallagher said she does not support the plebiscite plan, which is set to be challenged by advocates in the High Court.
"We don't believe that peoples' relationship should be subject to a popular vote before action is taken by the Parliament to ensure that there is equality," Senator Gallagher said on Wednesday.
"This matter went to the High Court by the ACT government, years ago. It was taken by the Commonwealth government to the High Court.
"The High Court found very clearly that it is the Australian Parliament that needs to determine this. Labor won't be changing our position."