A Sydney District Court jury found Paul Raymond Evans, 56, of Saratoga, guilty of 18 sex offences during his time as dormitory master at Boys' Town Catholic boarding school for troubled teenagers at Engadine.

He was in jail on Friday night after a judge refused bail.

The court heard Evans was charged and acquitted of sexual offences involving two teenagers in 1988 and was moved to St Patrick's parish at East Gosford in 1991 where he was assistant priest with the then Father Michael Malone, now the bishop of Maitland-Newcastle Diocese.

When Evans was moved to Kincumber parish on the Central Coast in 2002 he was known by locals as the "king of the kids" because of his close links with youth groups.

He was charged with new offences after a man approached Broken Bay Diocese, then the police. Six other men said they had also been abused.

Broken Bay Diocese Bishop David Walker said Evans was immediately stood aside and people in parishes where Evans had worked were asked to come forward if they had allegations of other offences.

"It is sad. I think every case is sad," Bishop Walker said.

There was "a bad dimension to the priest that's now been accounted for", he said.

But the man whose allegations led to the convictions said the five-year process adopted by the diocese was "like being abused all over again".

"It's been a bloody hard road. I got the ball rolling to weed this mongrel out but the church put everything on hold the minute I went to the police," he said.

Evans pleaded not guilty to 20 charges. He was found guilty of nine counts of homosexual intercourse, seven counts of indecent assault and two acts of indecency. He was found not guilty of one homosexual intercourse charge and one charge of indecent assault. He will be sentenced in September.