The law, introduced on Wednesday, states priests will risk three years jail time if they don't report child abuse revealed to them during the sacrament of confession.

Father Brendan Lee said he would rather spend the rest of his life in jail than break the sacramental seal.

"I will always keep the people's confidence, and that will always be my position," he said.

"Unlike the rule about priests not being allowed to marry that can be changed by the Pope with the stroke of a pen, the seal of confession is a doctrine of the church which means that nobody can change it - not even the Pope.

"It only has to be broken once, and it is gone forever."

Father Lee added that without the seal, people would be unlikely to admit their crimes.

"You can do more good by having the seal because if someone is going to admit a crime in the seal, you can work with that," he said.

"You can say 'you have to give yourself into the police'."

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Father Lee hoped the law wouldn't come into effect in NSW, but said, either way, he would not be compelled to obey it.

"I would rather go to prison," he said.

An advocacy group for people who were raised in orphanages, children's homes and foster care has publicly welcomed the moved.

Co-founder and CEO of Care Leavers Australasia Network Leonie Sheedy welcomed the bill.

"At long last Victorian children are going to be the priority," she said.

"We live in a secular country. Times are changing. The Catholic church doesn't wield power over the little people and the poor."

Ms Sheedy said she hopes to see the laws extend to NSW and the rest of Australia.

"Australian children have to be our highest priority," she said.

"When we were in those Catholic orphanages - children who lost their parents, lost everything, lost their siblings - we were invisible in our country, and that's why these abusers can get away with these crimes."

Ms Sheedy added any priests who did not agree with the laws should leave the country.

"If you don't want to abide by the laws of this nation, then go live in Rome," she said.

Attorney-General Jill Hennessy addressed reporters on Wednesday about the bill.

"I don't think in contemporary and mainstream times ... that we can do anything other than say the rights of children trump anyone's religious views," she said.

"Ultimately, this is about making sure that we start to right the wrongs of systemic abuse."