In this image made from video, Archbishop Philip Wilson, centre, heads to Newcastle Local Court, north of Sydney. Picture: Australian Broadcasting Corporation via AP

Canberra, Australia - An Australian archbishop on Tuesday became the most senior Roman Catholic cleric in the world convicted of covering up child sex abuse in a test case that holds to account church hierarchy that kept silent in the face of an international paedophile crisis.

Magistrate Robert Stone handed down the verdict against Archbishop of Adelaide Philip Wilson in Newcastle Local Court, north of Sydney, following a magistrate-only trial.

Wilson, 67, had pleaded not guilty to concealing a serious crime committed by another person — the sexual abuse of children by paedophile priest James Fletcher in the 1970s.

He had made four attempts in the past three years to have the charge struck out without a trial.

The conviction is another step toward holding the church to account for a global abuse crisis that has also engulfed Pope Francis' finance minister, Australian Cardinal George Pell.

Frank Brennan, an Australian Jesuit priest, human rights lawyer and academic, said Wilson had to stand aside as Archbishop of the South Australian state capital.

"I would think that the mind of Pope Francis at this stage would be that if there be a conviction of a bishop in relation to a failure to disclose abuse in circumstances where the state thought that was criminal activity, then I would think the mind of the pope would be that that doesn't measure up in church terms either and that therefore it would be impossible for someone to remain in the job as a bishop," Brennan said.

Brennan said Wilson had complied with the nondisclosure culture of the church in the 1970s.

"There's no doubt that Archbishop Wilson in recent years ... has been one of the good guys. He has been one of the bishops in the Catholic Church who has been trying to clean things up," Brennan said.

"But this relates to when he was a young priest. Even someone like him who later got it back in those years was so confined by our culture that it would seem there was no disclosure," he added.

An Australian inquiry into child abuse recommended in December that the Catholic Church lift its demand of celibacy from clergy and that priests be prosecuted for failing to report evidence of paedophilia heard in the confessional.

Australia's longest-running royal commission — which is the country's highest form of inquiry — had been investigating since 2012 how the Catholic Church and other institutions responded to sexual abuse of children in Australia over 90 years.

The report heard testimony from more than 8,000 survivors of child sex abuse. Of those who were abused in religious institutions, 62 percent were Catholics.

On Tuesday, Magistrate Stone told the court that Wilson had concealed the abuse of two altar boys in the Hunter Valley region, north of Sydney, by Fletcher by failing to report the allegations to police.

Stone said he was satisfied that one of the altar boys, Peter Creigh, had been a "truthful and reliable" witness.

Wilson was released on bail until he appears at a sentencing hearing on June 19. Prosecutors will argue for a custodial sentence.

In a statement issued by the Catholic Church, Wilson said he was disappointed by the conviction.

"I will now have to consider the reasons and consult closely with my lawyers to determine the next steps," he said.

Prosecutor Gareth Harrison had submitted that Wilson was involved in a cover-up to protect the church's reputation and that there were doubts about his honesty.

Harrison argued that in Wilson's mind, victims came second.

Wilson, who is suffering from the early stages of Alzheimer's disease but maintains that medication has helped his memory, told the court last month during his trial that he could not remember Creigh and another altar boy telling him in 1976 that they were abused by Fletcher.

The court has ruled that Creigh can be named in media reports, but that the second accuser cannot be named for legal reasons.

The prosecution argued that Wilson failed to give details to police about a serious crime after Fletcher was arrested in 2004 and went on trial for preying on another boy.

Fletcher was found guilty of nine counts of child sexual abuse and died in prison of a stroke in 2006 while serving an almost eight-year sentence.

Defence lawyers had argued that Wilson could not be found guilty because the case was circumstantial and there was no evidence to prove the archbishop was told about the abuse, believed it was true or remembered being told about it.

Defence lawyer Stephen Odgers urged the magistrate to take into account that in the 1970s, a priest having sex with a boy was not considered a serious indictable offence, the legal basis for the concealment charge against Wilson.

Odgers told the court the abuse would have been viewed as an act of indecency, not indecent assault, if the victim could not prove he had been forced to perform sex acts.

Former Police Detective Chief Inspector, who had previously made public allegations that the church had covered up Fletcher's crimes, said outside the court that he was "delighted" by the verdict because someone in the church was being held to account.  

"It's a major turning point. It's been very difficult for so many of these witnesses; I can't tell you how difficult it's been," Fox said.  

One of Fletcher's victims, Peter Gogarty, described Wilson's conviction as a "massive precedent."

"This will now open the doors for other jurisdictions to start looking at trying to prosecute people who deliberately looked after their institution and literally threw children to the wolves," Gogarty told reporters.

Daniel Feenan, whom Fletcher also preyed on, said if Wilson had gone to the police in 1976 - the year he was born - Fletcher "would never have got to me" and his life would have been very different.

AP