The Adelaide archbishop was charged on Tuesday with one count of concealing a child sex allegation made against the late Hunter priest Jim Fletcher in the 1970s, nearly nine months after the NSW Special Commission of Inquiry recommended the charge.

He is one of only a handful of Catholic clergymen in the world to be charged with concealing a child sex allegation against another priest, and only the third in Australia after the late Toronto priest Tom Brennan became the first to face such a charge in 2012.

Archbishop Wilson, the vice-president of the Australian Bishops Conference, denied the allegation in a statement on Tuesday and said he would vigorously defend the matter.

"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.

"From the time this was first brought to my attention last year, I have completely denied the allegation."

The archbishop has taken indefinite leave while he defends the matter.

News of the charge meant tears for some Hunter child sex abuse victims and survivors, and relief that police from Newcastle strike force Lantle had finally been able to lay a charge after concerns about the length of time Commissioner Margaret Cunneen's recommendation had been with the NSW Office of the Director of Public Prosecutions.

"I'm stunned. When I first heard about it I cried and cried," said Fletcher victim and longtime advocate for victims Peter Gogarty.

"This is an important step in the process of identifying who did know what was going on with these priests, and it's significant for anyone who has ever been sexually abused as a child, whether in the Catholic Church or other institution, or for that matter in their own home by a family member.

"What this says is that no-one's above the law."

He did not believe a senior Catholic clergyman would ever be charged with concealing a child sex allegation because "it was like a hill too high".

"But having said that this is an absolute tribute to everyone involved, and proof that our system of justice works."

Fletcher victim Daniel Feenan, whose allegations about the priest to Hunter detective Peter Fox in 2003 led to Fletcher's conviction and jailing until his death in 2006, said he was pleased and relieved.

"I wanted it (the charge against Archbishop Wilson) to happen, but I was concerned that through the process, no one had the balls to actually do it," Mr Feenan said.

"The church didn't think people like me would still hang on after all this time and expect people to be held to account, but we did, and this is a significant day."

A  Newcastle woman, 61, who was a victim of notorious Hunter paedophile priest Denis McAlinden, and whose documents led to the establishment of strike force Lantle, said she felt good on behalf of all children who had ever been sexually abused, and hoped it would give hope to children suffering child sexual abuse today.

"I didn't just do this for me. I did it for everyone who's felt powerless against someone more powerful. It's been a really long hard journey but it's been worth it.

"I didn't know what to say when the police rang to tell me he had been charged. I was in shock. I couldn't answer for a second. I had to get them to repeat it about 10 times. This is a Saint Patrick's Day we'll never forget.

"The Catholic Church has made out that we survivors were the bad people but we weren't. We were children. I'm absolutely disgusted with the church, and I'm glad people are being held to account."