New South Wales police are investigating complaints that Catholic Archbishop of Adelaide Philip Wilson mishandled sexual abuse cases involving fellow clergy in the 1970s and '80s when he was a senior priest.

One of the complaints comes from a Hunter Valley man who was abused by notorious paedophile Father Jim Fletcher in a house the Archbishop lived in.

Archbishop Wilson, who is widely tipped to become the next Archbishop of Sydney, denies any knowledge of the abuse.

But victims support group Broken Rites wants a full parliamentary inquiry to determine what senior members of the Catholic Church hierarchy knew about the abuse.

Yesterday ABC News Online's Investigative Unit reported on how Archbishop Wilson was coming under increased pressure to reveal what he knew about clerical sex abuse in the Maitland-Newcastle diocese.

From the late 1960s until the late 1990s more than 100 children were abused in the diocese, north of Sydney, by at least five priests.

Peter Gogarty was one of the boys who was preyed on.

"There was this incredible sort of inner turmoil about what is happening. What do I do? And I remember more than once going home and sitting in the toilet and crying," he said.

Mr Gogarty was a young teenager when he was abused by Fletcher in the same house Philip Wilson then lived in.

He says the Archbishop of Adelaide, who was then a senior priest in the diocese, should have known what was happening.

"Quite often I would be there alone with Jim, never without Jim, always with Jim, and [I] regularly saw Philip Wilson in that house," he said.

"Now why would any grown man, why would any adult think it was appropriate for another adult male - forget about whether or not he is a priest - what would any reasonable adult think of that sort of behaviour?"

'No knowledge of abuse'

The Archbishop has told the ABC he did see the young boy in the house but denies he ever saw him taken into a bedroom and knew nothing of the abuse.

"As far as he was concerned Jim was just a good bloke and he didn't know that Jim was up to anything untoward," Mr Gogarty said.

In the next two weeks another paedophile priest from the same diocese, Father John Denham, will be sentenced for the sexual abuse of 39 victims.

Many of them were from St Pius X High School in Adamstown, where Archbishop Wilson was then teaching.

Stephen Kilkeary was a student at St Pius from 1975 until 1979. He says it was a violent place where sexual assault was common.

"It was rampant, basically," he said.

"John Denham was basically very overt in his sexualised behaviours towards a whole lot of boys and again, thinking back over the years, he basically would target boys, would groom them, would go out of his way to sort of get into their lives, go to their parents' homes, take them on trips to Sydney, introduce them to alcohol - very full-on paedophile-type behaviours."

Mr Kilkeary says the question for him remains: was Archbishop Wilson aware of what was going on at the time?

"I've given that a lot of thought over the years and my view would be that it would be impossible for anybody not to know," he said.

Archbishop Wilson says he had no knowledge of the abuse going on while he was a teacher at St Pius.

The chairman of the Australian Catholic Bishops' conference also denies there was any cover-up over the handling of the sexual abuse of an eight-year-old girl by another priest in the same diocese.

But Broken Rites spokesman Dr Bernard Barrett says the abuse is endemic and he wants a full parliamentary inquiry.

"There probably needs to be an inquiry appointed by the State Government and headed by a judge or a retired judge to get to the bottom of all this and to make it report to Parliament," he said.

Police are still investigating victims' complaints in the Maitland-Newcastle diocese, including the accusation that Archbishop Wilson failed to report the sexual abuse of children to police.