The Catholic Church is no more legally responsible for priests who abuse children than a trucking company which employs a driver who molests women, Cardinal George Pell maintains.

Victims' families say it's a ludicrous comparison and even the chair of the child abuse royal commission thinks the situation is quite different when it comes to a priest getting access to a child.

Cardinal Pell accepts the church has a moral obligation to victims, but when it comes to its legal responsibility, the actions of its priests are not necessarily its fault.

"If the truck driver picks up some lady and then molests her, I don't think it's appropriate, because it is contrary to the policy, for the ownership, the leadership of that company to be held responsible," Cardinal Pell told the commission via video link from Rome on Thursday.

But Cardinal Pell said if the church had been warned about a priest or had bad policies or procedures in place, "then certainly the church official would be responsible".