Just came off the phone with TPG. I was advised that my call is recorded. I advised the representative that that I will then also record it upon which she advised me that that was not allowed. I insisted and advised her of the law here in Australia that if you have a one party recording the other party has the right to record it aswell. She advised me that she is not aware of the law in Australia. I then advised her that its the Law that she knows the law and that not knowing the law is no excuse. She advised that if I also wanted to record the conversation that it is TPG's policy to disconnect. She disconnected. This (and my recording) will go to consumer affairs. Dodgy stuff.
I would say have fun going to the consumer affairs. Legality of recording conversations are different for each state. Making a general statement saying that it is legal Australia-wide regarding the legality is you making a false statement. People are trained to take calls in the call centre and they are aware of it and they follow procedures.
I'm not sure myself regarding legality of recording a conversation between you a consumer and TPG as a business. But for a private individual to another individual conversation, some states would need the other party to consent to it. In this case, the call centre person did not consent and I assumed followed procedure. You could probably ask them not to record your conversation. If they reject that, then I think you could actually argue that they are not allowed to do so.