Scrap gay panic defence: SA Greens

South Australia has been urged to scrap the so-called gay panic defence in serious criminal cases.

The Greens say the defence - where a gay sexual advance can constitute provocation in certain murder cases - is outdated.

"This homosexual advance defence is homophobic, offensive and positively medieval," Greens MP Tammy Franks said on Monday.

The defence played a role in the High Court last week quashing the murder conviction of an SA man and ordering a retrial.

Under local laws, if the so called gay panic defence is accepted it can result in a murder conviction being reduced to manslaughter.

But the defence only applies if a man has killed another man.

It doesn't apply if a man makes a non-violent sexual advance towards a woman or if a woman makes a non-violent sexual advance towards a man or a woman.

Similar laws have been scrapped in all other states except Queensland where the government has announced it will move to also dump such provisions.

"We have come a long way towards overcoming discrimination and homophobia in this state, but this outdated gay panic defence relic still exists and it needs to go," Ms Franks said.