The Australian app is based on the Singapore app (yes THAT other country of great personal freedom).
This part is particularly scary: the app uploads "a list of anonymised ID's that your phone has been close to."
So you don't even actually provide the list of your contacts to the authorities. Your phone does that for you by "passively" collecting identifying data of all the other phones around you, and then uploading that data list to Big Brother.
this app is NOT about COVID19.