I see by your comment to @dw1 that you questioning what your insurance company says.
Let's be clear - what your insurance company says is not necessarily the law! @dw1's answer is the correct legal position.
"Knock for knock" is a commercial position adopted by Australian insurance companies in order to avoid expensive litigation when, in the scheme of things, who really cares. Now it may be (almost certainly is) a term of your contract with your insurance company that you accept their ruling on this if you want to make a claim on your policy. That would mean you would pay the excess and the accident would be on your record.
You do not have to do this.
If you can prove your version of events then you personally can sue the other driver for their negligence. What will almost invariably happen is that they will make a claim on their insurance who will either a) settle or b) defend your claim and launch a counter claim against you (which your insurer will have nothing to do with because you chose to go outside the policy). You then go to court and the magistrate will want to know a) why you are wasting their time with this trivial case and b) what the evidence says. They will either rule or, more likely, refer you to compulsory mediation. At this point you have to ask yourself, do I really have time for this?
I am not a lawyer, I am not your lawyer.