Adelaide Archbishop Philip Wilson had acted in a way "designed to protect the reputation of the Catholic Church" in not reporting a fellow priest's historical sexual abuse of altar boys, a NSW court has heard.

The claim was made as magistrate Robert Stone was preparing to rule on a last-ditch bid by Wilson, who's accused of covering up child sex abuse, to have the case against him dropped.

Mr Stone told the Newcastle Local Court on Tuesday he hoped to decide on a submission by defence barrister Stephen Odgers SC that Wilson had "no case to answer" by noon on Wednesday. But the ruling could come as late as Thursday.

Mr Odgers made the submission after prosecutor Gareth Harrison formally closed the crown case against Wilson on Tuesday.

The defence barrister said the case against Wilson was circumstantial and there was no evidence to prove beyond a reasonable doubt that then priest had been told about the abuse, believed it was true or remembered being told about it.

Two former altar boys claim they told Wilson in 1976 how priest James Fletcher had sexually abused them.

One of Fletcher's victims, Peter Creigh, says Wilson - then an assistant priest - had a "look of horror" when told but he never reported the matter to police.

The second victim, who can't be named, states Wilson told him the abuse claims were lies because Fletcher "was a good bloke".

Wilson, 67, is the most senior Catholic official in the world to be charged with concealing child sex assault.

Fletcher was found guilty in December 2004 of nine counts of child sexual abuse and died in jail of a stroke in January 2006.

Mr Odgers told the court on Tuesday the defence was not challenging Mr Creigh's truthfulness but there had to be real concerns regarding the reliability of his memory of the alleged conversation with Wilson.

But Mr Harrison said Mr Creigh did not waiver when giving specific evidence about his vivid memory of telling Wilson what Fletcher had done.

The prosecutor said after learning Fletcher was on trial in 2004 accused of sexually abusing four other young boys Wilson must have remembered what Mr Creigh told him in 1976.

He must have believed the abuse claims were true but still he didn't go to the police.

By failing to report the matter Wilson acted in a way "designed to protect the reputation of the Catholic Church", Mr Harrison added.

The "no case to answer" submission is Wilson's fourth attempt to have the case thrown out.

Mr Stone was the magistrate in February 2016 who initially refused to quash or permanently stay the proceedings, and then a NSW Supreme Court judge dismissed the archbishop's appeal against that decision eight months later.

The NSW Court of Appeal also ruled against Wilson in mid-2017.

The case finally began in December after Wilson was found fit to stand trial despite being diagnosed with the early stages of Alzheimer's disease.