Health authorities are racing to stem the damage from a new, mystery coronavirus cluster in Sydney's northern beaches that has grown to 17 new cases in two days.
The hundreds of thousands of residents of the peninsula have entered a quasi-lockdown, with NSW Health asking them to stay home as much as possible and not leave the area for the next three days.
Locals should avoid non-essential visits to aged care facilities and hospitals, and steer clear of high-risk venues like gyms and restaurants.
With just one week to go till Christmas, NSW residents will be anxiously waiting to see if the cluster spreads further.
Two northern beaches cases were announced on Wednesday evening, with three more described by health authorities at a press conference on Thursday morning.
News of 12 further infections came on Thursday evening.
Authorities believe an Avalon RSL band night might have acted as a super-spreader event.
One of the new cases is an aged care worker at the Pittwater Palms facility.
The source of the outbreak remains a mystery. Sewage testing last week uncovered no virus fragments in the area, indicating the virus was newly introduced to the northern beaches.
NSW Premier locks down nursing homes
NSW Premier Gladys Berejiklian on Thursday said northern beaches nursing homes will be locked down until the outbreak is contained, just a week after restrictions eased allowing unlimited visitors.
"We want to get on top of this and don't want this concerning us in the last few days before Christmas," Ms Berejiklian told reporters.
"There are a number of aged care facilities which are very vulnerable in the northern beaches ... we're recommending no visitors until we identify the source of the infection and feel more confident we have it under control."
The Pittwater Palms facility is closed to visitors, while those in contact with the infected worker are being tested and are self-isolating.
NSW's 12 consecutive days without a locally transmitted virus case ended on Wednesday after a Sydney airport driver tested positive and two cases popped up on the northern beaches - a woman in her 60s and a man in his 70s.
Health alerts have now been issued for a number of venues across Sydney's northern beaches.
The development comes after interstate travel restrictions had been lifted.
On Thursday evening, WA's premier Mark McGowan ordered anyone who entered his state from NSW to self-isolate for 14 days and get tested on day 11.
It comes as several other Australian states implement new travel rules for NSW residents, throwing Christmas plans into disarray for many families.
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