In December, 1998, agreement was reached by all State’s Ministers of Transport to implement national towing regulations. In essence, the national rules state that “A motor vehicle with a Gross Vehicle Mass (G.M.V.) not exceeding 4.5 tonnes must not, without the approval of an authority, tow a trailer with a mass (including any load) exceeding;
The capacity of the towing apparatus fitted to the vehicle, or
A relevant maximum trailer mass specified by the vehicle manufacturer.”
Put simply, the most you can tow is the amount specified by the vehicle manufacturer or the capacity of the towbar - WHICH EVER IS LEAST.
It seems some people have confused ideas about towing law. Its not at all strange to see a retired couple in their little Nissan's towing a 20 foot caravan down the main street holding up traffic, But truck driver is not allowed to tow their 18 foot semi trailer down that same street. The truck driver also needs to obtain a special license to tow a trailer.
A car driver is not allowed by law, to tow a registered car on a tandem trailer where it would be tied down and secure, but it can be towed by chain behind said car.
A learner driver is forbidden to tow any object behind a vehicle they are in control of, Yet a probationary driver which has only 120 hours driving experience can legally tow a 20 foot fully laden caravan or bigger they same day they get their P's!
Now you would think, with on average 1700 deaths on Australian roads each year, that the Australian government would put a stop to this silliness and rewrite some of these laws.
