I'm a registered tax agent. This isn't really true - but, it's exactly what someone needing a 2-ton codpiece would say.

If you use a passenger vehicle exclusively for work / business, then you can claim depreciation on it's total cost up to a maximum of ~$66k (last year... this limit is indexed each year).

Vehicles with a carrying capacity of > 1 tonne are not subject to this limit as they're "commercial" vehicles rather than passenger vehicles.

So if you had a $100k to spend on a new car, then a landcruiser wagon / SUV will be less tax effective than a RAM ute because you can't claim a deduction for the entire cost of the ute.

That said, no one actually chooses between those types of vehicles on the basis of the tax deduction available - you either want a ute or you don't. The choice is always between a hilux size ute and a ram size ute. Additionally, I don't have a list but I've heard tell that very few of the bigger utes actually have a carrying capacity of > 1 tonne once you subtract the potential weight of passengers.