I have shipped a lot of packs to Australia, they were not possible to track. I've fill out that form of Auspost lalst month and had response as below:
"Thank you for contacting us regarding a Registered Post International article that you posted to Australia. I have checked our systems and this article was delivered on 23 January. As the Registered Post International service is not a fully traceable service you are unable to retrieve information from our website. If you require an article to be fully traceable it needs to be sent using the Express Courier International (ECI or EMS) service, which is the only service we offer with this facility"
Aplication/contact link:
https://contactus.auspost.com.au/app/ask#emailI cannot understand that how it is not trackable in spite of we pay extra money to track. It is interesting.
Good Luck!