A northern Sydney hospital staffer is one of 10 new COVID-19 cases recorded in NSW as the state government implores people to play their part in preventing the spread of the virus during what it warns is a critical time.
The Hornsby Hospital healthcare employee worked in the emergency department on August 6 from 11am to midnight while infectious, the Northern Sydney Local Health District confirmed.
The worker wore a mask at all times while in contact with patients and was asymptomatic at the time, but became unwell after their shift.
Staff in contact with the worker have been identified and told to self-isolate for 14 days, while those who attended the hospital on August 6 are being chased up.
The worker was one of 10 new COVID-19 cases recorded in the 24 hours to 8pm on Saturday from 31,681 tests, with just one case in hotel quarantine.
A Pennant Hills church has also been closed for deep cleaning after a parishioner tested positive.
St Agatha's Catholic Church is working to trace people at a prayer group on Monday, August 3 between 7pm and 8pm, with anyone in attendance advised to isolate until contacted.
Anyone who attended the 6.30am masses on August 5 and 6 have also been told to be alert for symptoms.
Two further cases remain under investigation, NSW Health said on Sunday.
NSW Health's Dr Jeremy McAnulty urged people to get tested, practice social distancing and wear a mask if social distancing is not possible.
"Testing at even the slightest sign of symptoms and maintaining good social distancing is crucial at this stage of the pandemic," he said in a video update on Sunday.
"It is extremely important we all play our part in preventing the disease at all times."
NSW residents are now largely confined to their own state after Queensland closed its border, following similar moves by Western Australia, South Australia and Tasmania.
NSW has ramped up its own travel restrictions and is forcing residents returning from coronavirus-hit Victoria into two weeks of hotel quarantine.
Meanwhile, a second student at Tangara School for Girls in Cherrybrook has come down with COVID-19, with all students from years seven to 12 sent into two weeks of self-isolation. The secondary campus will remain closed until August 21.
Another confirmed virus case on Sunday is a household contact of a Tangara student.
Our Lady of Mercy College in Parramatta on Saturday night also confirmed a schoolgirl had contracted COVID-19 and deep cleaning and contact tracing was underway.
NSW Health also warned shoppers who attended Bunnings in Campbelltown in Sydney's southwest on August 4, 5 and 6 to be alert for COVID-19 symptoms after an employee tested positive. The worker wore a mask during their shifts.
Premier Gladys Berejiklian on Sunday warned against community complacency.
"No matter how tough, well-organised and well-resourced we are, we rely on all citizens doing the right thing, all of the time," she wrote in an open letter published in The Sunday Telegraph.
"It is sadly no exaggeration to say that when it comes to COVID, complacency could literally be the difference between life and death. Just one person can put the entire state in jeopardy."
There are currently 111 COVID-19 cases connected to the Thai Rock Wetherill Park cluster, 59 to the funeral events cluster and 34 linked to the Potts Point cluster.
Eight patients are currently in intensive care in NSW, with six on ventilators.