Child protection advocates are calling for a dramatic shake up of the system after it was revealed that in the last five years more than 12 people convicted of child sex crimes and assault have obtained a ‘working with children check’ in Victoria.

Offenders have won the right to work with children through legal challenges at Victoria's highest tribunal, in circumstances that advocates say drastically undermine Australia’s child protection system.

People convicted of such crimes who seek a ‘working with children’ check have their application automatically denied, however, are able to appeal the decision and a dozen refusals have been successfully challenged.