The child sex abuse royal commission has asked the Vatican to produce all documents relating to abuse complaints against its priests in Australia.

The royal commission into child sex abuse is investigating how the Vatican dealt with allegations of abuse against its priests in Australia.

Commission chair Peter McClellan has written to the Secretary of State of the Vatican City, asking for a copy of all documents held in Rome relating to complaints of sexual abuse by priests and religious leaders in Australia.

Justice McClellan hopes the documents will shed light on how complaints were handled by the Catholic Church.

“We have asked for copies of documents which reveal the nature and extent of communications between Catholic congregations in Australia and the Holy See,” Justice McClellan will tell Griffith University in Brisbane on Thursday.

“From these documents we should be able to determine how church authorities in Australia, under the guidance or direction of the Vatican, have responded to individual allegations of abuse.”

The commission has received some documents from the Vatican relating to its upcoming public inquiry of the Wollongong diocese.

But Justice McClellan says the Vatican has yet to respond to his request for documents relating to other sexual abuse complaints.

The Royal Commission into Institutional Responses to Child Sexual Abuse has so far heard allegations of abuse at the Scouts, YMCA, three schools, two church dioceses and the Salvation Army.

Justice McClellan warns that the potential for abuse still exists at those institutions.

“All of these institutions continue to exist (and) the risk of abuse accordingly remains,” he says.

Based on information the commission has collected, Justice McClellan says there are at least 30 other institutions which must be examined in public hearings.

A “significant portion” of the institutions reported to the commission by abuse survivors were faith-based, Justice McClellan says.

“Many of these are Catholic institutions,” he says.

Justice McClellan says the commission has received stories from more than 1730 people in private sessions and has referred more than 160 matters to the police for investigation.

The commission is due to provide an interim report to the federal government by June 30.