Is it illegal under the constitution for a state to close its borders to other Australians?

Media coverage

• Title	Is it illegal under the constitution for a state to close its borders to other Australians?
  Media name/outlet	ABC Online
  Country/Territory	Australia
  Date	22/04/20
  Persons	Lisa Waller

• Title	Is it illegal under the constitution for a state to close its borders to other Australians?
  Media name/outlet	ABC Premium News (Australia)
  Country/Territory	Australia
  Date	22/04/20
  Persons	Lisa Waller

• Title	Is it illegal under the constitution for a state to close its borders to other Australians?
  Media name/outlet	Ahlain News
  Country/Territory	United Arab Emirates
  Date	22/04/20
  Persons	Lisa Waller