The West Australian government has threatened penalties of $50,000 to those who refuse to self-isolate when instructed.
Queensland Premier Annastacia Palaszczuk said refusing to self-isolate could mean fines of $13,000 in her state.
While it began as a voluntary measure, self-isolation has started to become mandatory in some circumstances.
From midnight tonight, all international passengers arriving in Australia have to self-isolate for 14 days under strict new measures announced by the Federal Government today.