Victoria
Victoria has also reintroduced the 72-hour self-isolation requirement for all international arrivals.
All arrivals must have an international passenger travel permit and take a PCR test within 24 hours of arriving in the state.
They must take another test between the fifth or seventh day after arrival.
Unvaccinated travellers must spend 14 days in hotel quarantine.
Government sources said the Victorian Government was considering extending quarantine and reintroducing mask mandates in some settings.
New health orders could be announced as early as Monday, the sources said, and were likely to be also rolled out by state and territory leaders across the country.
Queensland
Doubt has been raised whether Queensland will push ahead with its plans to reopen its state borders when 80 per cent of its residents have been fully-vaccinated.
The Sunshine State was expected to hit the target between December 6 and 12 - just weeks before Christmas.
Queensland deputy chief health officer Peter Aitken said he could not guarantee the borders would be reopened without quarantine.
Travellers could be forced to isolate if they visit hotspots in NSW and Victoria.
Deputy premier Steven Miles reassured that 'nothing has changed at this moment'.
'So nothing has changed at this stage, but people should be assured that we will continue to take a cautious, well-prepared approach,' he told reporters on Monday.
'Our officials are amongst the best in the world. 'They will monitor the situation very, very closely and they'll provide advice to us.'
Currently, Queensland plans to scrap quarantine for fully vaccinated domestic travellers once 80 per cent of eligible state residents are fully vaccinated.
It then plans to scrap quarantine for vaccinated international travellers once 90 per cent of Queenslanders are vaccinated.
International arrivals are currently required to go into hotel quarantine while returned travellers from states with open borders must go into home quarantine.
Western Australia
Premier Mark McGowan on Saturday evening shut his state's borders to South Australia in a draconian effort to lock out the mutant new strain, as it allows in visitors from NSW and Victoria.
The ruling means only vaccinated South Australians can enter WA,
