How close can I be to the airport fence?

Just wondering how close your allowed to be to an airport fence and if there is any restrictions. For context this is in QLD, Australia airport YEML. I have been right up to the fence before and an airport safety car has come and stopped at the end of the runway looking at me but later left, and no one has said to step away. Photos of how close it is to the runway are below. Thanks if anyone can help, cheers.