A Catholic priest has taken up the fight to have allegations of a homosexual advance struck off Queensland's law books as a defence to murder.

Father Paul Kelly first became interested in the legal loophole when a man was murdered on his church grounds in Maryborough in July 2008.

The defence the victim had made a homosexual advance was used in an attempt to downgrade the charge to manslaughter and while it did not work Father Kelly was still shocked it could even be brought up in the first place.
"It's extremely upsetting and worrying, I was following the trial with great interest and then there was this talk that he (the victim) had made some sort of homosexual advance," he said.

"I never heard of something so terrible, that there is some kind of defence that says if you make a homosexual advance then that can be used in court. I just can't believe in this day and age that can be any kind of defence to hurting someone."

Father Kelly has now launched an online petition to lobby the state government to have the law changed.

The petition was launched last week and after enough signatures are garnered Father Kelly plans to take it to the Premier and LNP leader Campbell Newman.

Father Kelly said although his main reason for wanting the loophole closed was because a homosexual advance should never be used as an excuse for violence, there were a number of other factors at play.

He said a defence of a homosexual advance should not be allowed to be brought up in court because it could possibly prejudice the jury even if the allegations are proven false.

"By mentioning (homosexuality) might be a factor, it seems to increase the tolerance that violence has been used," he said.

"I find that pretty astounding."

Father Kelly said he hoped people would not find it odd a Catholic priest was campaigning for the law change.

"The church has always defended basic human rights, it's never said intolerance or violence should be tolerated," he said.

"It's a powerful mix of paranoia and intolerance that means people can get their charge downgraded to manslaughter if there was a homosexual advance. It's not about gay rights, it's about human rights."

The petition comes after Attorney General Paul Lucas told brisbanetimes.com.au in April that the passing of the Criminal Code and Other Legislation Amendment Bill 2010 had closed loopholes around the partial defence of provocation. 

"No longer can mere words alone, including gay or straight advances, be sufficient for the defence of provocation, except in the most extreme and exceptional circumstances," Mr Lucas wrote in an opinion piece in response to calls for change.

However, senior law lecturer in law at the University of Newcastle, Alan Berman, said the concept of "exceptional circumstances" was open to interpretation and could include "a non-violent homosexual advance".

"Exceptional circumstances could be a gay proposition," Dr Berman said. "And in most cases [defence counsel] allege it wasn't only a verbal proposition but they might have gently touched them, or touched their leg and it might have sent them into a fit of rage."