Australian child sex abuse victims on Friday began a journey half way around the world to watch the Vatican's Australian-born finance director testify in Rome about his knowledge of child molestation within the Catholic Church.

Cardinal George Pell will give evidence on Monday to Australia's long-running Royal Commission into Institutional Response to Child Sexual Abuse, via a videolink from a Rome hotel, after his lawyers cited health concerns preventing his travel to Australia.

The Commission bowed to requests by victims groups' to allow them to watch Pell, 74, give evidence in person. A crowdfunding page set up by a local radio station has raised A$204,000 to fly 10 victims and five counseling and medical support staff to Rome.

"It's about being in that room and bearing witness, which for us is re-empowering and helping heal the community," Peter Blenkiron, 53, who was abused at the age of 11 by a Christian Brother at his school, told Reuters.

While Pell is not personally being investigated for criminal offences by the Royal Commission, as Australia's most senior clergyman he has become the focal point for victims' frustration over what they say has been an inadequate response to abuse claims from the Catholic Church.

The Royal Commission declined to provide details on security arrangements at the hotel, where Pell is scheduled to give evidence for three or four days. The sessions will run from 10pm to 2am Rome time.

Pell is expected to be asked about his knowledge of measures taken by the Roman Catholic Church to handle child abuse complaints in the town of Ballarat, 112 kms (70 miles) west of Melbourne, where he was born and served as a priest from 1973 to 1983. He went on to become archbishop of Melbourne and Sydney, before his Vatican appointment in 2014.

"We just want an acknowledgment, if Pell said 'what we did was wrong and it will never happen again', I would be the first to shake his hand," said Blenkiron, who is from Ballarat.

Pell has testified twice before at the Royal Commission, which last year heard that priests suspected of abuse in Pell's former diocese were moved between parishes and put in church-appointed rehabilitation instead of being reported to police. Pell has denied those allegations.

Pell has blamed a former culture of silence in the church for the cover-up of child abuse by clergy, making it difficult to know the full extent of abuse. He has twice apologised for the church's slow response and said hundreds of people in Australia had received compensation for abuse.