Australia has a mandatory level of insurance called Compulsory Third-Party insurance or CTP. It is required by law for all registered motor vehicles in all states and typically covers in the order of $20m or so of third-party medical expenses and/or compensation related to an injury sustained in an accident. Property damage is not covered.

As for relative price typically one would be looking at around $300-600 per year, depending on age, driving history, type of car etc. Granted with our universal health care I suspect that our average out-of-pocket medical expenses for injuries from car accidents are lower than the US.