Not especially applicable to border lockdowns within Australia.
The biggest case that hit the Federal Court was the border closure by the State of Western Australia (population ~ 2 million, land area 3x Texas) which was in effect the local citizens of W.Australia being damn near 100% in lockstep with their elected local representatives in saying we have no desire to see free movement of people across our State border during the time of the pandemic.
They were in opposition to the Federal Government and the PM's office and held their ground ..
.. despite the alleged "immense power concentrated in the PM's offices".
Free trade of goods continued via rail, road, and shipping so their was no issue with that part of the Consttitution, and the lockdown was in keeping with earlier (2005 etc) biosecurity ammendments in both State and Federal law.