Mr Gogarty and the founder of Survivors of Clergy Abuse Australia, known as Cathy, will urge the NSW government to immediately abolish all church-based internal investigative processes because "the public needs to take decision-making out of church hands".

Mr Gogarty and Cathy will tell Mr Hatzistergos that Australia is 10 to 15 years behind America, Ireland and some European countries where inquiries into the church's handling of sexual abuse have been held, and law enforcement agencies have investigated church cover-ups.

Cathy will urge Mr Hatzistergos to replace internal church investigative processes such as Towards Healing with a government-controlled system such as that used in Queensland, where victims use sexual assault disclosure statements, rather than statements to church representatives, to make their claims.

"The system we currently have leaves the institution responsible for these crimes in charge of looking after the victims," Mr Gogarty said.

"The people who've got the most to gain from keeping these issues in-house are making the decisions, and you have to wonder in what other situation would people find that acceptable?

"Under the existing system of Towards Healing there's not really any encouragement for people to go to the police. They're vulnerable, and the very institution that allowed the crimes against them, is supposed to now act in their best interests."

Mr Gogarty said the need for a formal inquiry was urgent, particularly given church concessions that the sexual abuse issue was not just confined to individual paedophile priests.

"What we're arguing is that somebody needs to take this out of the Catholic Church's hands because it seems incapable of acknowledging the systemic issues such as who moved the priests from one area to another after complaints were made.

"In Australia, like in other countries, we need an independent inquiry about who knew what about these priests, when did they know it, and what did they do about it?"