Federal and state attorneys-general meeting in Adelaide on Friday agreed to three principles for the laws, which were recommended following the Royal Commission into Institutional Responses to Child Sexual Abuse.

Those principles say that "confessional privilege" can't be relied upon to avoid a child protection or criminal obligation to report beliefs, suspicions or knowledge of child abuse.

They also dictate that clergy would not be able to use that defence to avoid giving evidence against a third party in criminal or civil proceedings.

Work on such laws is already well under way in most states and territories, but legal expert Luke Beck said the agreement will implement a nationwide standard.

"Some states are already in compliance with this and they don't have to do anything else," said Mr Beck, an associate professor at Monash University.

"Now, all have signed up and said 'yes, we're going to do it'."

Teachers, police and medical practitioners are already legally required to report child physical and sexual abuse allegations.

The Catholic Church has insisted priests would be obliged to defy the laws, with Melbourne Archbishop Peter Comensoli previously stating he was prepared to go to jail rather than break the confessional seal.

"For Catholics, confession is a religious encounter of a deeply personal nature. It deserves confidentiality," he said in August.

Australian Associated Press