A young girl was woken from her bed and driven by her own father to be left with paedophile priest Gerald Ridsdale who then sexually abused her, a court has heard.

Ridsdale, arguably Australia's most notorious paedophile priest with past convictions for assaults on more than 50 children, on Tuesday formally pleaded guilty to sexually assaulting another 12 children, including the girl, when he was a priest in Victoria.

He pleaded guilty to 23 charges, including two counts of rape and one of buggery.

Ridsdale told one altar boy the abuse was "part of God's work", the Victorian County Court heard.

A day after findings were handed down in the royal commission into child sexual abuse, Ridsdale, 83, used a walking frame to enter the County Court dock and kept his head bowed as more of his devastating offending was outlined.

Prosecutor Jeremy McWilliams said the latest admissions involved 11 boys and a girl who Ridsdale sexually assaulted between 1962 and 1988 while he was a priest in Ballarat, Mildura, Horsham, Edenhope and other locations.

One of the victims, Mr McWilliams said, was a girl who was eight or nine when she was woken by her father one night and driven to a church where Ridsdale was waiting. The father left his daughter with the priest, who sexually assaulted her.

On another occasion the father took his daughter to a confessional room, where Ridsdale was again waiting. Ridsdale pleaded guilty to buggery in relation to the charges against the girl.

The victim, who now experiences "crippling" flashbacks and has been consumed by fear most of her life, told the court the offending had caused her hurt, anger, rage and disgust.

"I feel like a piece of meat handed around for anyone to take a bite of," she said in a victim impact statement read to the court by the prosecutor.

The woman said sadness had felt normal throughout her childhood, and that her brain had not developed properly because of the abuse, which in turn affected her ability to learn and dream of a future.

"Good things just didn't happen to me," she said.

Mr McWilliams said Ridsdale abused his position as a priest to befriend and then abuse the children, who were aged between six and 13. Some of the children were altar boys while others knew him as a family friend.

Ridsdale is already serving a long jail term after previously being convicted of sexually assaulting more than 50 children.

The royal commission heard in 2015 that it was unclear how many children he had abused over the years, but that he was able to continue his crimes when the church shuffled him from parish to parish despite its knowledge about him.

Mr McWilliams said one boy recalled being raped several times, and the abuse worsened when the boy's father was sick in hospital.

After one assault, Ridsdale told him: "Don't tell your mum or dad, or your dad could die".

That victim addressed the court and told Ridsdale his conduct had been "despicable", and that the abuse had destroyed relationships within his family.

"I hate the limitations you have put on my life," the man said. Ridsdale had his head bowed.

Ridsdale, the court heard, told another boy he raped: "God will forgive all of your sins".

He also told the boy that God would punish his family if he told anyone.

Nine of the victims were in court on Tuesday, while another appeared before the court via video link from prison.

At the start of the hearing, defence counsel Tim Marsh said Ridsdale had fallen and fainted on Tuesday and had been advised by medical staff he shouldn't attend court but he insisted he wanted to be there.

Mr Marsh said Ridsdale knew what he was doing was wrong and took advantage of the venerated position clergy were held in at the time.

Ridsdale was "clearly a repugnant figure to many", who would welcome the prospect of the 83-year-old dying in jail, Mr Marsh said.

But he called on Judge Lawson not to change Ridsdale's current earliest possible parole date of April 2019.

In 2015, Ridsdale told the royal commission he was sexually abused as a child.

One of his victims urged Judge Irene Lawson to consider the impact of Ridsdale's crimes before she handed down her sentence.

"I am in my 36th year of a sentence for a crime I did not commit. My sentence is for life," he said.

The man has depression, anxiety and post-traumatic stress disorder and said his struggles had cost him his marriage and career.

He blamed himself for once getting caught alone with Ridsdale, having been warned about the priest by other children.

"I am a survivor. I am good at surviving but not good at living ... I desperately want to stop surviving and start living," he said.

Judge Lawson choked back tears as she told the man he was not responsible for something that happened when he was a nine-year-old boy.

Judge Lawson will sentence at a later date.

In 2014, Ridsdale had his jail term extended when he pleaded guilty to more sex crimes against children.

The latest admissions mean his jail term could be again increased and he could die in prison.

The hearing continues.

Anyone needing support can contact Lifeline on 13 11 14.

With AAP