Clarky - a fascinating idea that you would "drag all the states into line and impose harsh restrictions".
Check out the Federal Constitution - wartime is definitely a federal issue as is national border control, passports/visas etc, but health is not.
However even the so-called "Border Force" is only a re-badged customs and excise branch, the way I read it the State Police retain most of the powers, and the Federal Health and Education Departments only wield power because Canberra has all the money.
The Federation is showing cracks under the COVID-19 attack because the States retain all powers not mentioned in the Federal Constitution, that includes health, education, state border control, shopping hours, liquor licensing and most draconian of all - police and civil liberties.
It will be interesting to see how Australia, as a Federation, survives this plague.