An urgent search is underway for the source of a coronavirus outbreak at a Western Sydney school, which has so far resulted in three Omicron cases.
The health department is investigating the cluster at Regents Park Christian School, where 13 Covid cases have been confirmed.
Urgent genome testing is underway on the remaining 10 cases to determine if they are also the Omicron variant.
“The whole school K-12 has now been dismissed for the year. All students and staff have been identified as close contacts,” the health department said.
“They must get tested and self-isolate according to NSW Health guidelines.”
The health department also advised Sydney Indoor Climbing Gym is being considered a venue for possible transmission after a case visited there last Saturday between 9am and 4.30pm.
"This is of concern to the extent that this is the first case that we know of that appears not to have had any travel history," Health Minister Brad Hazzard said.
"It would appear that the case could well be an on-NSW-soil transmission."
Mr Hazzard said the fact school had been dismissed "is convenient".
"The ones who need to are obviously being tested, (those) who are in the cohorts with the relevant students," he said.
Another child, who visited businesses in Chatswood, has also been found to have the Omicron variant.
The family - which had not been in southern Africa - is in special health accommodation.
Countries in southern Africa are of particular concern to health authorities.
But NSW Health is concerned the family caught the virus while flying into Sydney on Qatar Airways flight QR908 from Doha on November 23, and is contacting other travellers on that flight.
NSW Health reported 337 cases of the coronavirus in the 24 hours to 8pm on Thursday - the highest tally in six weeks - but no new virus deaths.
Premier Dominic Perrottet again urged the public not to focus on case numbers.
"We would have expected those numbers to be much higher in circumstances where we opened up our state," he said.
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