One of Australia's worst child-sex offender priests, Gerald Ridsdale, has pleaded guilty to a string of new abuse charges against 11 children.

Ridsdale pleaded guilty on Thursday to 20 historical abuse charges. This included 14 counts of indecent assault, two counts of buggery, two counts of rape, one count of attempted rape and one count of taking part in an act of sexual penetration of a child.

Convicted paedophile priest Gerald Ridsdale has pleaded guilty to 20 more abuse charges. Credit:Damian White

Prosecutors withdrew 18 more charges against Ridsdale.The crimes occurred between 1962 and 1988 in various places around the state, including Ballarat, Edenhope, Merbein, Riverside, Mortlake, Quantong and Burnt Creek.

Former Ballarat Bishop Ronald Mulkearns - who died last year - moved Ridsdale to various parishes around Victoria over about three decades where he continued to abuse children, despite persistent allegations of child sexual abuse against him.