Many states in Australia have had mandatory 14-day quarantine in hotels for all overseas arrivals (air and sea) at the state's cost since mid-March. There is very little that can be done about it. There are also many interstate travel restrictions and quarantine requirements for those hoping to move around within the country.
Fairly archaic treatment of people, and at times there have been humans rights' implications (most notable the inadequate assessment of 'detainees' mental health issues, including a suicide while in quarantine).
On a positive note, the majority of Australia's COVID cases had origins from overseas travelers and this mandatory quarantine has assisted in controlling numbers.