This past case dealt with a Crown appeal in circumstances in which two coaccused convicted of armed robbery, aggravated burglary, false imprisonment, had given undertakings to assist authorities in the prosecution of a co-offender, but had changed their position and decided not to cooperate. The Court of Appeal re-sentenced the offenders.
See http://www.austlii.edu.au/au/cases/vic/VSCA/2003/14.html.