The law in Australia differs from one state/territory to another. More importantly, it is very different from the USA's law. You might think that whatever occurs in American movies apply to similar situations in Australia. This is NOT true. For example, the article below provides an overview of what can be considered self-defence in New South Wales. 

https://www.sydneycriminallawyers.com.au/blog/what-amounts-to-self-defence-in-new-south-wales/