I've just picked myself up a Polaris side by side and would like to take it into some national parks but I can't find online what the requirements are.
Generally registered vehicles only on gazetted roads to my knowledge.
On a side note, don’t buy parts in Australia. Anything major you will pay no more than half the price shipped from the us. I made the mistake of buying one too. Cheers
Short answer, legally you can't. Lifesaride is correct - NSW National Parks and NSW State Forests are registered vehicles only, and (with some very very minor exceptions) you can't register an ATV, quad etc. You can register a dirtbike - which is why you can go dirtbiking in state forests.
In vic definitely no quadbikes. They can be registered but then they cannot be driven on public roads unless it's just to cross them if they run through your property (as an example) side by side I am unsure.
I think better is to get a Suzuki Jimmy or similar and put normal road reg on it
I don't know if they have changed, but I worked for the Forestry back in the 90's, all state forest areas fell under the definition of a public road under the Traffic act, therefore vehicles had to be registered and drivers/riders licensed.