Advocates for a "no" vote on same-sex marriage are calling for the Federal Government to "override" anti-discrimination laws during any future plebiscite campaign.

The Australian Christian Lobby (ACL) wants to ensure the "no" camp can speak freely during the debate.

But those advocating for same-sex marriage say it is an unreasonable request and that both sides should be capable of a respectful campaigns that comply with existing laws.

All states and territories currently have these existing laws, prohibit discrimination on the basis of sexuality.

ACL managing director Lyle Shelton said those laws will have to change to allow its supporters to freely express their opposition to same-sex marriage in any future plebiscite.

"We're concerned about people being taken to human rights commissions around Australia simply for advocating marriage between a man and a woman and right to the child to, wherever possible, be allowed to be loved and raised by their mother and father," Mr Shelton told PM.

He argued that Christian leaders had already been unfairly targeted for promoting marriage between a man and a woman.

Mr Shelton used the example of the Catholic Archbishop of Hobart, Julian Porteous, who had to answer to Tasmania's Anti-Discrimination Commission after distributing booklets supporting "traditional" marriage.

"We've seen the Archbishop of Hobart, Julian Porteous, taken to the Tasmanian Human Rights Commission simply for distributing a very respectful booklet on marriage, and people are wondering all over this country if you're going to speak out loud that marriage is between a man and a woman, and risk being taken to a government commission, then that's a really chilling break on free speech."

The Federal Government has not yet considered a formal proposal for a plebiscite on same-sex marriage, but Mr Shelton said he was concerned those who intend to vote "no" to same-sex marriage would be afraid to voice their opinion in the public domain without recrimination.

"I don't think anyone in Australia would ever have thought that just for speaking about marriage between a man and a woman and a right to children, not vilifying or being disrespectful to anyone, but simply talking about marriage and distributing literature about it in a respectful way, that you could end up in front of a government commission," he said.

"I think the threshold for offence under many of these state-based anti-discrimination laws is way too low."

Current anti-discrimination laws protect 'both sides'

Those in favour of redefining marriage to include same-sex couples have said the current anti-discrimination laws are adequate.

Australian Marriage Equality director Rodney Croome said the existing laws protected both sides of the debate.

"If it does descend into hatred and vitriol, then I think people on both sides need protections that are there already from our Anti-Discrimination Acts to ensure that the debate stays respectful," Mr Croome said.

Mr Croome added that neither the "no" or "yes" camp should resort to changes in the law to have a meaningful debate.

The Australian Marriage Equality organisation wants both sides of the debate to be able to engage in respectful campaigns. ( AAP: Carol Cho )

But Mr Shelton is not convinced.

"Well Rodney is the one who told people to report the Catholic Bishops Conference to the Government," he said.

"So we're very worried. He (Rodney Croome) thinks that what was distributed through Catholic school communities was illegal."

Rather than changing the law, Mr Croome suggested both sides sit down to discuss how to approach the same-sex marriage debate.

"What I'd like to see, instead of the suspension of anti-discrimination laws, is for representatives of both sides of the debate to sit down together and nut out a framework for how to conduct a plebiscite campaign in a way that's as free and respectful as possible."

Attorney-General George Brandis is overseas and unavailable for comment.

Human Rights Commissioner Tim Wilson also declined to comment.