The Archbishop of Melbourne, Denis Hart, described the figures as "horrific and shameful".
They were released in a submission to a state parliamentary inquiry into the handling of abuse cases.
Campaigners say the true number of abuse victims could be up to 10,000.
In its submission, the church said the 620 cases went back 80 years with the majority taking place between the 1960s and the 1980s.
It says it is still investigating a further 45 cases.
In a statement, Archbishop Hart said it was important to be open "about the horrific abuse that has occurred in Victoria and elsewhere".
Watch a report on Australia's cases here (Thanks to msloane for the link)