A plebiscite on same-sex marriage risks unleashing hate and division in the community and would create a dangerous political precedent, former High Court justice Michael Kirby has warned.

Key points: If politicians have an issue they do not want to address, the precedent will allow them to send it to a plebiscite, Kirby says

If politicians have an issue they do not want to address, the precedent will allow them to send it to a plebiscite, Kirby says But he concedes a plebiscite is not unlawful

But he concedes a plebiscite is not unlawful Kirby says other social issues were not voted on in a plebiscite

The Turnbull Government is pushing ahead with a nationwide vote, with advice from the Australian Electoral Commission recommending it be delayed until next year.

But Mr Kirby warned the move would allow politicians to shirk their responsibilities

"It will mean that any time that there is something that is controversial, that is difficult for the parliamentarians to address, or they don't want to address, they'll send it out to a plebiscite," Mr Kirby said.

"We spend a lot of money and we have big campaigns and an awful lot of angst and we elect the politicians and this issue has not been given a fair trot in Parliament, it hasn't really been properly considered."

In 2013, the High Court unanimously dismissed the ACT Government's law which sought to legalise same-sex marriage, deciding Federal Parliament has the sole power to deal with the issue.

Mr Kirby was not a High Court judge at the time.

Plebiscite 'alien to constitutional tradition'

He conceded a plebiscite was not unlawful but argued it was against the spirit of the constitution.

"The fact that we haven't had a plebiscite in a hundred years is an indication that its just alien to our constitutional tradition," he said.

He pointed out other social issues had not been voted on in a plebiscite, such as abolishing the White Australia Policy, advancing women's rights and disability issues.

"Why are we now picking out the LGBT, the gay community? It is simply an instance of hate, of dislike, hostility to a small minority in our population, its un-Australian."

Most Australian referendums have failed, and the former judge worries the gay marriage plebiscite will face similar difficulties.

He said he thought it would be better to "sit it out" until there was enough support for a parliamentary vote to legalise same-sex marriage than hold a national vote.

Former justice Kirby is gay and has been with his partner Johan van Vloten for almost 50 years.

In a blog post on his website, Mr Kirby said no-one had come up with an explanation why his relationship with Mr van Vloten undermined others.

"No-one has satisfactorily explained how my 40-year relationship with Johan in any way affects [still less undermines] their heterosexual marriage," he wrote.

Mr Kirby announced he was gay in 1998, two years after he was appointed to the High Court, by updating his entry in Who's Who, a catalogue of influential Australians.

On his website, he said he "certainly" would not have got a position on the High Court bench if his sexuality was made public.