I have a Toyota Prado with a ball weight of 2500 kgs is their a Legal way to increase this as I'am looking at a new van that require's a ball weight of 3000 kgs.

Whoops! I think you have a typo.
The maximum ball weight for the Prado is 250Kg, not 2500Kg.
Ozjohn.

Hi Gearingup

As far as I know, the only way to increase the towable weight from 2500kg-3000kg is to change vehicles to a model that can legally tow that weight ie, Land Cruiser, Nissan Patrol etc

I had the same problem with my 07 Pajero. If your looking for a new van then you are limited to vans that comply with the vehicles specifications. The Prados specs would be 250kg ball weight and 2500kg ATM.

Vince