Defence counsel Shaun Ginsbourg, in his closing address to the County Court in the trial of former Salesian College priest David Edwin Rapson, told the jury the allegations dated back too far for a jury to find them true.

Mr Rapson, 60, has pleaded not guilty to eight charges of indecent assault and five counts of rape related to alleged incidents between the mid 1970s and 1990 while he was a priest at the boarding school in Rupertswood.

One of the complainants alleges he was raped on four separate occasions in 1990.

The jury will begin deliberations on Wednesday.

Mr Ginsbourg said the age of the allegations, along with supporting evidence and a lack of witnesses, made it difficult for jurors "to accept these allegations beyond reasonable doubt".

"It makes it hard for you to convict Mr Rapson on the age of the complaints ... a generation has passed," he said.

"The lapse of time should make you more careful in accepting that these allegations are true."

The trial has previously heard Mr Rapson drank alcohol and smoked cigarettes with the boys and lured them to his office with the offer of playing computer games.

Mr Ginsbourg acknowledged that in doing that, Mr Rapson had "crossed the line" in terms of mixing with children, "but that doesn't make him a sex abuser".

He said there were inconsistencies in the complainants' evidence, and variously described the men as confused, unreliable and mistaken.

He said one of the men was motivated in making allegations against Mr Rapson because the complainant was later jailed for sexually penetrating a 16- or 17-year-old child.

Mr Ginsbourg told the jury Mr Rapson had been eager and comfortable to answer questions when interviewed by police, and had denied the allegations when they were first put to him.

"He could have taken the easy option and not answered the questions," he said.

Judge Liz Gaynor instructed the jury on Tuesday afternoon and told them to begin deliberations on Wednesday morning.