The Australian states of New South Wales (NSW) and Victoria, as two major entry ports of the country, have introduced 72-hour isolation requirements for all international arrivals as health authorities scramble to sequence for the new Omicron variant in arrivals from southern African countries.
NSW health authorities confirmed on Sunday morning two of 14 arrivals from southern African countries had tested positive for COVID-19 and had begun urgent genomic sequencing for the Omicron variant.
The variant, believed to be more infectious than all previous strains, was first detected in South Africa and flagged as a "variant of concern" by the World Health Organization (WHO) on Friday.
All recent arrivals from nine southern African countries were urged by NSW health authorities to self-isolate for 14 days, while passengers from flights with positive cases would be quarantined in a special health facility.
Despite mounting fears, NSW Premier Dominic Perrottet said the state would stick to its reopening plans "for the moment".
"This is a reminder that there is a long journey to go, and we think we have always had a fair and balanced approach," Perrottet told local news outlet Sky News.
On Saturday afternoon Australian federal Health Minister Greg Hunt announced that non-residents would not be able to enter Australia from nine southern African countries and all flights from these countries would be suspended for 14 days as a "matter of precaution".
Dr. Deborah Cromer at the Kirby Institute of University of New South Wales (UNSW) said while it is "unsettling" the emergence of a new variant was not unexpected.
"Viruses constantly mutate and take on new forms, and the level of existing immunity against a new variant is key in determining the impact an emerging strain will have," said Cromer.
She said that border closures would only help buy time for scientists to determine the effectiveness of existing vaccines against the new variant.
"Closing borders may buy us some time to gather the data to answer these questions (vaccine efficacy against Omicron), however, as we have seen previously with both the original strain and with Delta, a virus will ultimately find its way past these barriers," she said.
No cases of the Omicron variant have been confirmed in Australia.