Negligently or willfully obstructing, hindering or preventing the free passage of traffic is an offence. It’s also an offence to cause unreasonable inconvenience to other motorists, and that’s the law under which blocking someone’s driveway falls.
If your driveway is blocked then you can report it to Police who then may issue a ticket against the offending vehicle, but unfortunately they don’t have the power to remove the vehicle.
In fact, it’s quite difficult to get the car removed without committing an offence yourself unless it is stolen, abandoned or involved in an offence.
If you have a persistent problem you can apply to your local council for an official no parking sign, e.g. this page for north Sydney council.
Can you park across your own driveway?
The answer is yes, but only for two minutes to drop off or pick up passengers. Council officers and police don’t know that it’s your car that is across your driveway and therefore will ticket it. Also, blocking the driveway blocks access to emergency services and prevents other vehicles from using it to turn around.
Its presence can be obstructive for people in wheelchairs who use the lower kerb to cross the road.
In some cases, parking across a driveway can obstruct other motorists’ view of the road.
You must also not park in your own driveway if your vehicle remains on or across the footpath as this causes an obstruction for blind people, people pushing prams and so on. That part of your driveway is owned by the council, not by you.
The fine is $106 and can be issued even if just a small part of your vehicle juts out.