I just recently saw this on the VicRoads website:
Full Link:
So... the way it reads leads me to believe you have to apply for an exemption and the car must be either one of these:
* turbocharged or supercharged with a power to weight ratio of less than 100kW per tonne
* turbocharged or supercharged with a power to weight ratio between 100kW and 125kW per tonne and that is considered to be a family type vehicle (4 seats or more) rather than a sports type vehicle. A family type vehicle is a sedan, station wagon or hatch normally used to carry families/passengers with 4 or more seats and are equipped with child restraint anchorages. A family type vehicle does not include a sports car (two door coupe).
On those grounds I think you could get away with a 'rolla but not a 180.