The most senior Catholic official in the world to be convicted of concealing child sex crimes must be jailed to send a message that institutional cover-ups will no longer be tolerated, a NSW court has heard.
Adelaide Archbishop Philip Wilson stood aside but refused to resign after he was found guilty in May of failing to report to police the repeated abuse of two altar boys.
Magistrate Robert Stone on Tuesday said the archbishop would be sentenced in early July.
Pedophile priest James Fletcher indecently assaulted Peter Creigh on multiple occasions in the NSW Hunter region during the 1970s but when the child reported it to Wilson the clergyman did nothing.
Prosecutor Gareth Harrison said there was a "breach of trust" between the vulnerable youngster who - along with another altar boy - came forward in 1976.
"A 15-year-old boy came to him for help ... this wasn't a split-second decision," the prosecutor told Wilson's sentencing hearing at Newcastle Local Court on Tuesday.
"He thought he'd gotten away with this for all those years.
"He lied and the root of each of those lies is the unflinching loyalty to the Catholic church and protecting it at all costs."
Mr Harrison argued the 67-year-old should be locked up to deter other religious leaders, to denounce the conduct and to recognise the harm done to the victims.
Defence barrister Ian Temby QC argued Wilson may not survive being jailed which would likely worsen the senior cleric's many chronic illnesses and put him at risk of violence from fellow inmates.
Wilson suffers from diabetes, heart and Alzheimer's disease and depression, which would further deteriorate behind bars and "may even threaten his survival", Mr Temby said.
But Mr Harrison noted there was no evidence to suggest Wilson would be attacked in jail and his medical condition wasn't an excuse for him to escape punishment.
"Ill health cannot be a licence to commit a crime," he said.
The archbishop's legal team argued he should instead be given a good behaviour bond. The offence carries a maximum two-year jail term.
Mr Temby stressed Wilson was a trailblazer in introducing church police checks and compliance systems in Australia.
"The offender is not just a man who has no prior convictions but is, in fact, a man of prior positive good character with particular reference to the general field of prevention of child sexual abuse," Mr Temby said.
Fletcher was found guilty in December 2004 of nine counts of child sexual abuse. He died in jail of a stroke in January 2006.
The magistrate rejected claims by Wilson that he could not remember the children's allegations.
Wilson stood aside from the Adelaide archdiocese following his conviction in May and said if it became necessary for him to resign he would do so.
The hearing continues with Mr Stone to reserve his sentencing decision until July 3.