Information from the Caravan Industry Association of Australia:
If you are completing modifications to your vehicle to increase the Aggregate Trailer Mass (ATM*) rating of your Towable Recreational Vehicle.
*Please note some states refer to this as a GVM.
- Only the original manufacturer or an authorised Vehicle Inspector/Engineer is permitted to make a change to the vehicle ratings;
- It may be a requirement that both the original vehicle plate and the revised plate are affixed side-by-side on the modified vehicle, to record the history of the upgrade;
- Consumers may need to inform their insurance company of the vehicle modifications to ensure continued coverage.