Michael Aulsebrook, 63, a repeat pedophile offender, indecently assaulted the boy aged about 11 during the camp he managed while a Salesian brother in the 1980s.

The victim had complained of chafing after going to the beach and then jumping on a trampoline, so Aulsebrook took him to a first aid office and locked the door.

He gave the boy soft drink and got him to take off his shorts before rubbing and complimenting his genitals.

The brother also repeatedly digitally penetrated the child, patted his head, told him not to say anything about what "we" did and gave him lollies.

Aulsebrook was jailed in Victoria's County Court on Monday for 20 months after pleading guilty to indecent assault.

He was ordained as a priest a year or two after the abuse, which occurred in either 1985 or 1985, but left the Salesian order in 2004 after other crimes came to light.

"You are the architect of your own misfortune," Judge Gavan Meredith told Aulsebrook, who had previously said he'd lost his connection to the church since being revealed as a pedophile.

His holiday camp victim told the court Aulsebrook's abuse had damaged his relationships, including with his children.

The victim still finds it hard to trust people and feels like "less of a person" because of what Aulsebrook did.

Aulsebrook is already in jail for crimes including the drugging rape of a 12-year-old boy while a teacher at Sunbury's Salesian College, Rupertswood boarding school in 1988.

He has also previously been sentenced for indecently assaulting two girls, aged seven and 14, in 1983.

Judge Meredith accepts the former priest is sorry for what he's done and says he has reasonable prospects of rehabilitation.

Aulsebrook must spend another 22 months in jail before becoming eligible for parole.

Australian Associated Press