Instead, the head of the Canberra-Goulburn archdiocese says separate laws that will require all adults to notify police about child sex crimes will make the confessional clause "obsolete".

From Monday, ministers of religion will have to report allegations of child abuse to the ACT Ombudsman, regardless of whether the accusation came through the confessional.

In a letter to parishioners on Wednesday, Archbishop Christopher Prowse said that Catholics wanted to comply with the government's legislation "along with good citizens".

However he restated that priests would not break the seal of confession to report child abuse.

Instead, the priest hearing the confession would encourage the person to self-report the abuse outside the seal, Archbishop Prowse said.

He also said separate laws passed last week that would require all adults to report child sexual abuse or face two years in jail would negate the need to priests to report information from the confessional.

He described those laws as a "real gamechanger", that would "sensitise the community to this issue like never before".

"I see it that the confessional will not become the battleground for criminality and that it will not be necessary for us to have these sorts of hypothetical discussions because it’s already out in the community," Archbishop Prowse said.

Asked whether it was a good look for the church to refuse to comply with child protection laws given the findings of the Royal Commission Into Institutional Responses to Child Sexual Abuse, Archbishop Prowse said: "It depends where you look at it".

"I think the optics of everybody in the ACT responsible is a great look and I believe that’s going to render the idea of matters being negotiated of a criminal nature in the confessional, will make it obsolete, largely obsolete," he said.

Archbishop Prowse also reiterated that it was unlikely abusers would report abuse through the confessional.

Vicar General Father Tony Percy said even if they did, it was even more unlikely the priest would be able to identify who had disclosed the abuse.

"These types of confessions are most likely to be heard in jail when in fact the crime has been reported so we should be realistic about these types of scenarios," Father Percy said.

If a child abuser did confess to a priest, Archbishop Prowse said they would be strongly encouraged to report to the authorities.

A different, but similar approach would be taken if a child told a priest in confession that they had been abuse, Father Percy said.

"If a child comes it’s different. You explain to the child, this is not a sin, it’s not your sin so let’s talk about this outside the confessional," he said.

However Institute for Professional Standards and Safeguarding manager Maria Hicks said there were many more pathways for children to report abuse these days, and she would be surprised and saddened if it came through the confessional.

"We absolutely believe our children these days and if a child comes and says something to them, our parents, I like to think our parents respond, today we would believe it a lot more but if not them our teachers in our schools, our workers in Marymead, in Catholic Care, they’re all trained to recognise the signs of serious harm and do something about it," she said.

Ms Hicks said all child abuse complaints made to the diocese had to come through her and she was "first and foremost ... a mother of three children".

She also said the culture in the church had changed so much that "even an acolyte who might process up the aisle and back with a child" must have a Working With Vulnerable People Check.

Archbishop Prowse said parents of children in the Catholic school system should feel reassured by the "increasingly strong Catholic culture of child safety".

“I do have a real commitment in my heart to do all I can as the Archbishop of this place and elsewhere in my other responsibilities to make sure this is something front and centre of all our pastoral response," Archbishop Prowse said.