NSW has confirmed a seventh case of the Omicron variant, in a traveller who had not been in the countries of concern.
The traveller arrived in Sydney on Tuesday last week, two days before the most recent previously known case.
Everyone who arrived on flight QR908 from Doha on November 23 is being asked to get a PCR test immediately and isolate while they wait for further advice.
NSW Health is concerned transmission occurred on the flight, given the confirmed case had not been in the eight southern African countries of concern.
Two other members of their family have also tested positive for COVID-19 and genomic sequencing is under way to confirm if they have Omicron too.
They're all now isolating in special health accommodation.
Since arriving in Australia on Tuesday last week until Tuesday this week the person has been staying at the Mantra Serviced Apartments at Chatswood, and anyone who attended that venue during that week is now a casual contact.
They're required to get tested and isolate until they receive a negative result.
While NSW is so far relying on its high vaccination rate rather than additional lockdowns as the threat of Omicron is assessed, Health Minister Brad Hazzard has encouraged the uptake of booster shots to maintain protection after a 40 per cent increase in the uptake since last week.
Mr Hazzard said 500 previously tested swabs of travellers who had returned to NSW since November 22 had also been lab tested to ensure they did not contain the Omicron strain.
The jury is still out on whether the latest strain is more dangerous and could overwhelm hospitals, or merely be more transmissible and able to replace stronger variants.
NSW Health said at least two people with the Omicron variant have been in the community because they landed in Australia before quarantine rules changed on Saturday.
A woman in her 30s from the Central Coast and a man in his 40s from Cabramatta in Sydney's southwest, are both infected with Omicron and arrived on the same Qatar Airways flight from Doha a week ago.
Mr Hazzard said the Cabramatta community was on high alert but stressed the infected man had only visited one shop on Monday.
"There have been no further indications of transmission in that area," he said.
All of the 271 cases recorded in NSW in the 24-hours until 8pm on Wednesday were the Delta strain.
No deaths were recorded while 81,877 people were tested.
It is less than two weeks before more restrictions are lifted in NSW, and the unvaccinated will be able to return to hospitality venues and all shops.
Some 94.6 per cent of people 16 and older have had one vaccine dose while 92.6 per cent of adults have had both.
More than 81 per cent of teens aged 12-15 have had one shot while 76.8 per cent are fully vaccinated.
There are 144 people in hospital, including 24 in ICU and 10 ventilated.
