Adelaide Catholic Archbishop Philip Wilson has been charged with concealing child sexual abuse.

The charges relate to Hunter region paedophile priest Jim Fletcher, who worked with the Archbishop in NSW in the 1970s.

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Wilson announced in a statement he would take leave from his position after being notified of the charges filed against him by NSW Police.

NSW Police said its operation, Strike Force Lantle, launched in 2010, investigated allegations of concealment of serious offences related to child abuse by clergy "formerly and currently attached to the Maitland-Newcastle Diocese of the Catholic Church".

They alleged that Wilson, 64, concealed a serious offence.

He is due to appear in the Newcastle Local Court on April 30.

Wilson is a former Bishop of Wollongong, where he was known as a "healing bishop" for his handling of child-abuse scandals.

Wilson to 'vigorously defend innocence'

Wilson issued a statement acknowledging the charges filed against him by police.

Wilson said he will "vigorously defend his innocence" after being charged with concealing child sexual abuse. ( Alan Porritt: AAP )

"The suggestion appears to be that I failed to bring to the attention of police a conversation I am alleged to have had in 1976, when I was a junior priest, that a now deceased priest had abused a child," he said.

The statement said that the allegation was first brought to his attention last year and he "completely denied" it.

"I intend to vigorously defend my innocence through the judicial system and I have retained senior counsel, Mr Ian Temby AO, who will represent me in respect of it," Wilson said in a statement.

In the statement he referred to his participation at the Royal Commission into Institutional Responses to Child Sexual Abuse in NSW and SA and said his evidence at the hearings was indicative of his efforts to "best-practice child protection measures".

"I would like to take this opportunity to reaffirm my commitment to dealing proactively with the issue of child sexual abuse and the implementation of best-practice child protection measures which I have pioneered since becoming a bishop," he said.

Important day for Australia: child abuse victim

A victim of Fletcher, Peter Gogarty, said he felt overwhelming relief that a police investigation had resulted in charges against the Catholic Archbishop.

"I think it's a very, very important day for Australia, that we've now had someone in such a high position charged," Mr Gogarty said.

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"I hasten to add, everyone in this country is entitled to the presumption of innocence, but...the fact that our legal system has decided to charge someone this senior is enormously significant."

Pat Feenan's son Daniel was abused by Fletcher and said it had been a "long and hard journey" for him.

"I'm just very proud of my son and I'm proud of all the victims who have had the courage to stand up," Ms Feenan said.

"The fight's not over, the journey's not over, I'll keep working to support victims."