Scott Morrison said on April 3rd that people with working holiday visas in Australia are supposed to register a self-isolation at Australia.gov.au:
For working holiday makers who are looking to engage in those occupations as they regularly do. They will be required to self isolate and to go on to Australia.gov.au and register for self-isolation and do that where they are now for a period of 14 days before they transfer to another part of the country out in a rural or regional area. At that time, their employer will be looking to see that they have conducted that self-isolation before they would be employed in that work.
The problem is the form doesn't appear to exist in that site.