GTM (Laden weight) of 750kg upper limit for no brakes Australia Wide. I reckon many with no brakes would be pushing over the limit. Our Ct (which has mechanical and electric brakes fitted) has an unladen weight of 550kg. When I put it over the weighbridge, total trailer laden weight (GTM) was well over 1000kg.
A full water tank, gas bottles, fridge and cooling gear would take ours well over 750kg, without all the other stuff, tables, chairs, food, shainsaw, extra water, etc, etc.
If you use for off road, I see electric brakes as a must have.
see:
http://www.campertrailers.org/towing_regulations.htm