Problem there is people play the game by leaving on one passport, but when they need to come back to Australia to get away from Covid they whip out their Australian Passport and demand to be let in
I had looked into this. When you present a foreign passport to leave “they” will see you do not have a visa for Australia and will ask how you entered the country. This force you to show a NZ or AUS passport anyway, so now you are sprung.
The reality is they know if you are an Australian citizen, your name and DOB will flag on the Border Farce system.
We are all being distracted, lock down is only needed because they cannot get us vaccinated due poor management of the purchase of vaccines.
Then they can open borders like most of the world.