NSW Health has confirmed that two overseas travellers who landed in Sydney on Saturday night are infected with the new Omicron variant of concern.
Both passengers came to NSW from southern Africa and tested positive for Covid-19 late last night, officials said.
Urgent genomic sequencing confirmed the infections are the new strain, which early evidence suggests is more contagious.
The two positive cases are fully vaccinated and asymptomatic. They have been in isolation in the Special Health Accommodation since landing in Australia.
The passengers were among 14 people from southern Africa who arrived on Qatar Airways flight QR908 from Doha.
The other 12 passengers are also isolating in quarantine at the facility.
All other 260 flight passengers and air crew are close contacts and have been told to isolate.
On Saturday, Australia shut its borders to nine southern African countries, prompting NSW, Victoria, SA and the ACT to bring in new rules for all international arrivals amid concern over Omicron.
NSW Health Minister Brad Hazzard said not much is known about the new strain, though it may be more transmissible than Delta.
In particular, the effectiveness of current vaccines against Omicron is still being established, he said.
Mr Hazzard said it only took the Delta variant three weeks to reach 53 nations.
The United Kingdom, Germany and Italy announced on Saturday that they have detected cases of the new Omicron coronavirus variant.
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