Various legislation protects private land and Crown Land from illegal entry. In general, if it’s fenced off, it’s “Inclosed Land”.
Some roads pass through private land and have gates so if you are transitioning please ensure you close them properly after passing through.
Here’s a small sample of legislation about this.
Unlawful entry on inclosed lands
Offensive conduct while on inclosed lands
Penalty on leaving gate open
Liability of vehicle owner for certain offences