Under NSW law, cats are allowed to roam free. Rangers cannot simply pick up stray cats – they might be someone's pet.
Rangers can only seize a cat in areas where they are prohibited, such as a wildlife protection area, commercial kitchen, restaurant or café. Rangers can also seize cats that have injured a person or another domestic animal.
Thats from Sydney council page. Looks like ive been fooled! I still dont like cats and if one was hanging around my property id want to get rid of it..a nice good spray with the hose should work