My comment goes to the point of the thread. Whilst the vast majority of all CC transactions are made electronically these days, then per se there is no cash transaction, thus those transactions (over)paying the ATO is not likely to fall under the auspices of AUSTRAC. Putting my mind to the point, the only ways I can see one would happen is if said cash transaction is made via a bank teller or ATM, both of which would be reportable events to AUSTRAC if they exceeded the thresholds.
You only partially quoted what I typed, as I continued "with a particular focus on anti-money laundering and terrorism related transactions, after all the legislation sitting behind AUSTRAC is after all "[FONT=&]The [/FONT]Anti-Money Laundering and Counter-Terrorism Financing Act 2006[FONT=&] (AML/CTF Act)"[/FONT]