The AFP will be able to ask anyone for ID and eject them from the airport as part of a 2018 budget announcement. Under existing laws, police can only demand ID if they have reasonable grounds to suspect someone is involved in criminal activity.
Home Affairs Minister Peter Dutton commented
There's certain conditions that need to be met at the moment before police can ask for that identification. Which is an absurdity and it’s an issue that the police have raised with us. So we're addressing an anomaly and a deficiency in the law at the moment.The new rules will not require domestic travellers to carry ID.
We can presumably expect calls for similar checking by state/territory police at other transport nodes, such as major rail stations, and public/private entertainment or retail facilities.