Residents in Greystanes, Berala, Auburn and Lidcombe with any symptoms are urged to get tested.
Ms Berejiklian flagged introducing tighter restrictions to Greater Sydney if more cases emerged that had no known links to established clusters.
“If we get to a stage or if we feel that there’s too many cases that are completely unlinked or unrelated or something pops out unexpectedly that does cause concern then of course we’ll adjust our settings if that’s the case,” Ms Berejiklian said.
“Dealing with this pandemic is an evolving situation and every day things can change. Every day the government will consider new settings if we need to … that includes looking at events, looking at venues, looking at various settings we have across Greater Sydney and NSW,” she said.
On Saturday, northern beaches residents will learn what relief from almost two weeks of restrictions awaits them.
Lower northern beaches residents will learn whether they are to be absorbed back into Greater Sydney and under the same restrictions. The upper northern beaches’ position is more precarious, accounting for more than 90 cases in the cluster to date.
“It gives us greater heart that most if not all of the community transmission has really been stomped out in that region,” Ms Berejiklian said.
The three new western Sydney cases announced on Friday bring the total number of cases in NSW since December 16 to 173.
The last time NSW saw a similar increase in cases was in July following the superspreader event at the Crossroads Hotel in Casula when NSW went from zero new daily cases to 155 in 14 days. It took 116 days to get back to zero new locally acquired infections.
NSW Health authorities had a breakthrough after genomic sequencing showed the Croydon cluster in Sydney’s inner west was linked to the northern beaches outbreak. The person-to-person connection between the two clusters has not yet been found.
The two cases recorded in Wollongong are also genetically linked to the Avalon cluster.
Investigations have also found a case from the Croydon cluster and a case from the Wollongong cluster attended the Swallowed Anchor restaurant in Wollongong on December 19.
“This was before either the case from the Croydon cluster or the case from Wollongong had their infection, and what we’re looking at is whether they were both infected at that time and date,” Dr Chant said.
“There may have been a person at that restaurant who unknowingly had COVID at that time who had exposures or links to the northern beaches venues. It is critical we get to the bottom of this and so I urge everyone at that venue [to get tested],” she said.
Two Victorians who travelled to NSW on December 30 have also tested positive to coronavirus. Contact tracing was underway after they visited the Great Southern Hotel in Eden between 5pm and 6.30pm, and at Bermi’s Beachside Cafe in Bermagui from 9am to 10am, on December 31.
More than 32,000 people were tested in the 24 hours to 8pm on Thursday and the Avalon cluster grew to 146 after two previous mystery cases were linked to it.
Prime Minister Scott Morrison praised Australians for getting tested in large numbers. Forced to remain in Canberra, he said he understood the frustrations of people caught by border closures which were inconsistent across the country.
Victorians have been rushing to return home before the state’s border closed to NSW at 11.59pm on New Year’s Day, with motorists jammed in traffic lines reportedly stretching up to 40km.
NSW Police Minister David Elliott said Victorian Premier Daniel Andrews and other states have over-reacted to the situation in NSW.
“They’re not taking into consideration the population and the percentage of people … that are being diagnosed with COVID-19 so I’d like to see them opened as soon as possible,” he said.
“We need to make sure that we put it all into proportion. We are a nation, we’re not a collection of nation-states.”
A total of 63,109 Australians have returned from overseas between September and December 30.
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Anna Patty is a Senior Writer for The Sydney Morning Herald with a focus on higher education. She is a former Workplace Editor, Education Editor, State Political Reporter and Health Reporter.
Kate Aubusson is Health Editor of The Sydney Morning Herald.
Josh Dye is a news reporter with The Sydney Morning Herald.