Millions of Sydney residents were asked to limit their mobility over the Christmas holidays, with some families in lockdown and festive gatherings limited to 10 visitors indoors, as officials try to contain a COVID-19 outbreak which now totals 100.
Australia's most populous city has been virtually isolated from the rest of the country with state border closures or mandatory 14-day quarantine for Sydney arrivals.
"Please limit your mobility," New South Wales (NSW) state Premier Gladys Berejiklian told reporters in Sydney on Thursday.
"Apart from those close family gatherings, which we have allowed over the Christmas break, we don't want people moving around unless you absolutely have to."
The neighbouring state of Victoria on Thursday advised its residents not to "hug or kiss" any visitors who had been in Sydney in the past 10 days.
More than a quarter of a million people in Sydney's northern beach suburbs remain in some form of lockdown on Christmas Eve after a new coronavirus cluster emerged there last week.
Authorities are concerned infections may spread city-wide and are daily issuing an ever-growing list of potential transmission sites across the city and calling on people to be tested and isolate.
NSW Health said a record 60,000 coronavirus tests were carried out in the 24 hours to 8:00pm Wednesday.
Sydney recorded nine new local COVID-19 cases on Thursday, up from eight the previous day as a lockdown and social restrictions seem to be containing the fresh outbreak.
Berejiklian said a decision on whether to extend restrictions will be made on December 26.
Before the Sydney cluster, NSW had gone a month without any locally acquired infections, and officials are still struggling to determine the source of the outbreak. Genomic testing found the virus strain came from the United States.
All arrivals in Australia undertake a mandatory hotel quarantine, though some aviation workers are able to self-isolate without stringent supervision.
Two international airline crew have tested positive and been placed in Victoria's hotel quarantine programme this week, said the state's commander of COVID testing programme Jeroen Weimar.
In Queensland state, a crew member of a luxury superyacht recently arrived from the Maldives has tested positive in the port of Cairns.
Australia has reported just over 28,000 coronavirus cases and 908 deaths.