The most senior Catholic to be charged with concealing child sexual abuse — Adelaide's Archbishop Philip Wilson — has been found guilty by a New South Wales court.

The 67-year-old was accused of covering up abuse by priest Jim Fletcher in the NSW Hunter region in the 1970s.

The prosecution has requested a custodial sentence for Wilson, for reasons of "deterrence" and "denunciation".

Wilson remains on bail on the condition that he attends his sentencing hearing, which will be held on June 19.

The harshest sentence Magistrate Robert Stone is able to give is two years in prison, and he has the option of suspending the sentence.

Witness was truthful and reliable

Wilson's legal team made four attempts to have the case thrown out, arguing it was not in the public interest and that his diagnosis of Alzheimer's should preclude him from trial — although it did not preclude him from retaining his position in the church.

His lawyers maintained throughout the trial in Newcastle Local Court that while victim Peter Creigh was abused by Fletcher as a child, Wilson, who was an assistant parish priest in East Maitland at the time, did not know about it.

Mr Creigh previously asked for a non-publication order on his name to be lifted.

He clutched his partner's hand as Magistrate Stone read out the verdict before a packed courtroom.

The magistrate said he found Mr Creigh to be a truthful and reliable witness.

"I am satisfied and find that Mr Creigh described to the accused he performed fellatio of Fletcher and masturbated Mr Fletcher," Magistrate Stone said.

© AAP Image Archbishop Philip Wilson. Wilson 'wanted to protect church's reputation'

Magistrate Stone said he did not accept Wilson could not remember a 1976 conversation, in which Mr Creigh, who would have been aged 15 at that time, described his abuse at the hands of Fletcher

The magistrate said Mr Creigh "had no motive or interest to deceive or make up the conversation".

Magistrate Stone said Wilson knew "what he was hearing was a credible allegation and the accused wanted to protect the church and its reputation".

The magistrate said if Wilson had reported what he knew to police, it would have helped in prosecuting Fletcher.

He said Wilson knew the Creigh family.

"He knew what the young man was telling him was believable," Magistrate Stone said.

Magistrate Stone said he accepted Wilson had no role in the assaults and that Fletcher had never made admissions to him.