New South Wales has recorded nine new locally-acquired COVID-19 cases from almost 40,000 tests on Christmas Day.
Health authorities said eight of the infections recorded in the 24 hours to 8pm on Friday are directly linked to the Avalon cluster, six of which were household contacts of prior cases.
The ninth case, based in Bondi, may be a false positive and has no connection to the now 116-strong Avalon cluster, the source of which remains unclear.
It comes after the state recorded seven new COVID-19 cases in the 24 hours to 8pm on Thursday, nine the previous day and eight on the two days prior to that.
Premier Gladys Berejiklian announced that stay-at-home restrictions would return for residents in Sydney's Northern Beaches for three days - from midnight tonight until 11.59pm on 30 December.
"What our strategy is to nip this in the bud as soon as we can, to make sure we do the hard yards now so we can have normality as soon as we can," Ms Berejiklian said.
Indoor gatherings are banned in the Northern Beaches. Outdoor gatherings for exercise or recreational activities will be allowed for five people, including children, in northern section of the Northern Beaches.
That number increases to 10 for the southern section of the Northern Beaches.
Northern Beaches residents must stay within their locality, with Greater Sydney residents banned from entering the region.
Ms Berejiklian said a decision is yet to be made on what arrangements would be in place in place on New Year's Eve.
"Everybody should assume they're watching the fireworks from home this year," she said.
The nine new cases came from around 40,000 tests, a number that Chief Health Officer Dr Kerry Chant said she was very pleased with over the Christmas period.
"Thank you to the people who got tested in the period. Maintaining high testing rates is going to be essential to give us the best information to advise the government on the next steps," Dr Chant said.
Meanwhile, a passenger on flight ZL6469 from Sydney to Griffith on 21 December has tested positive to the virus, with 28 other passengers on the flight told to isolate and get tested.
The flight departed Sydney at 2:10pm and arrived in Griffith at 4:20pm.
Police from the NSW public order and riot squad were called to help break up
NSW Health Minister Brad Hazzard condemned the gathering, saying the risk taken is unacceptable.
"I am hoping it will not become a super spreader event. But there is every chance that it could be," he said.
"If they were in Europe right now, most of them would be in lockdown and not even allowed outside the front door. The fact that you can go out is a privilege, and it should be respected in an appropriate way."
What's happening around the rest of the country?
Meanwhile, Victoria notched up its 57th consecutive day without a locally-acquired COVID-19 case.
Chief Health Officer Brett Sutton said in a statement that there were zero new local COVID-19 cases in the state and zero new cases in hotel quarantine. The tally came from almost 5,000 tests.
Queensland also recorded no locally-acquired infection, but found one new case in hotel quarantine.
It comes as Queensland Police continue to investigate in the north of the state, carrying people on board who have since tested positive to the virus.
Meanwhile, Western Australia recorded six new COVID-19 cases, all of which are in hotel quarantine and related to returned overseas travellers.
People in Australia must stay at least 1.5 metres away from others. Check your jurisdiction's restrictions on gathering limits. If you are experiencing cold or flu symptoms, stay home and arrange a test by calling your doctor or contact the Coronavirus Health Information Hotline on 1800 020 080.
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