All overseas travellers arriving into New South Wales, Victoria and the ACT will have to self-isolate for 72 hours upon arrival as fears grow about the new hyper-infectious Omicron variant of Covid.
The new quarantine restrictions came into effect at midnight on Saturday and require all international arrivals in the three states - including the fully vaccinated - to be tested when they land.
The three state governments announced the change just hours after Australia closed its border to nine African nations - South Africa, Lesotho, Botswana, Zimbabwe, Mozambique, Namibia, Eswatini, Malawi.
Returned travellers from those countries must enter hotel quarantine for 14 days on arrival into Australia.
The introduction of self-isolation rules in the three states comes only four weeks after Victoria and NSW removed hotel quarantine requirements for fully-vaccinated travellers on November 1.
All overseas travellers arriving into New South Wales, Victoria and the ACT will have to isolate for 72 hours upon arrival amid fears of the growing Omicron African variant of Covid-19. Pictured are overseas arrivals on November 1 at Sydney Airport as hotel quarantine requirements were removed in NSW
Those arriving from overseas into the ACT will need to isolate until midnight next Tuesday
The ACT ended hotel quarantine for overseas arrivals on November 12.
The Victorian health department says the new rules will apply to unvaccinated children under 12 and unaccompanied minors, along with any household contacts of the returned traveller.
All airline cabin crew arriving from overseas into NSW will also have to isolate for 14 days or until their next departure.
These rules are slightly different in Victoria with vaccinated cabin crew to isolate for 14 days if they had been to one of the nine African countries of concern.
Western Australian Premier Mark McGowan earlier on Saturday evening shut his state's borders to South Australia in a bid to lock out the mutant new strain.
The ruling means only double-vaccinated South Australians can enter WA, where they must immediately go into quarantine for 14 days.
The changing of border rules comes amid fears the newly-named Omicron 'super-variant' is already in Australia via a repatriation flight from South Africa.
There are 20 returned travellers quarantining in the Northern Territory who were repatriated from South Africa last week - one of whom has tested positive to Covid.
Chief Medical Officer Paul Kelly said authorities were also in the process of tracking down about 100 Australians who recently arrived from the blacklisted countries and will now need to go into quarantine for two weeks.
New quarantine measures have also been introduced for airline cabin crew (pictured are health workers at Melbourne's Tullamarine Airport)
There are currently no known cases of the Omicron variant in Australia, Federal Health Minister Greg Hunt said (pictured nurse preparing Covid test for passenger)
United States and Europe earlier placed six countries on the red list before Australia added another three - Malawi, Mozambique and Seychelles
The new rules include banning non-Australian travellers from the regions, enforcing supervised quarantine for returned passengers and suspending all flights from the nine countries for two weeks.
'There are currently no known cases of the Omicron variant in Australia,' Health Minister Greg Hunt said.
Professor Kelly warned it was too early to tell if Australia would be plunged back into lockdown if the virus made its way across the Indian Ocean.
'In terms of ruling in or out, what else we might do, as the health minister has clearly said, we will do what we need to do,' he said. '
'At this stage, to move toward speculation about where we might end up in Australia, even if it came here and we don't have it here yet, that is premature.'
He said there was too little information about the current variant to make any long-term decisions.
The UK confirmed its first two official Omicron infections on Saturday, with Germany and the
