If only 2 cars are involved in the accident, the car which hits from behind is liable in most circumstances.
In 3 or more car pile-ups, it is necessary to determine whether the car immediately behind hit first or whether it had stopped in time and was pushed by the car behind it. If the latter case can be clearly determined then the car at the rear is responsible.
If it cannot be determined who was at fault and you are not insured, a claim can be made to the Queensland Civil and Administrative Tribunal (QCAT) if the amount of your claim is less than $25,000. You will need to name both parties as the first and second defendants.
In situations where a car rolls back into a stationary vehicle behind, it is the front car that is liable regardless of how close the rear vehicle was behind. In the absence of any independent witnesses however, it is often difficult to prove a situation such as this, unless the owner of the forward vehicle willingly admits liability.