Technology companies such as Facebook and Google would be forced to give Australian security agencies access to encrypted data under legislation to be introduced by the Turnbull government.

But the government has refused to say how the security agencies would access the data.
https://www.theguardian.com/technology/2018/jun/06/planned-laws-to-force-tech-firms-to-reveal-encrypted-data

Also see:

Australia ‘10 years behind’ on laws for digital assets
The number of dead Facebook members will soon outnumber the living ones, but when it comes to the handling of our affairs, digital assets such as online accounts are often overlooked, as the law is yet to catch up.
https://www.lawyersweekly.com.au/biglaw/23395-australia-10-years-behind-on-laws-for-digital-assets