Sydney's usually bustling harbourside restaurants were shuttered and city streets nearly deserted Saturday as a two-week lockdown began across Australia's largest city to contain a rapidly spreading outbreak of the Delta coronavirus variant.
More than 80 Covid-19 cases have been reported so far in an infection surge linked to an international flight crew transported to a quarantine hotel from the airport.
The flare-up was a shock for a city that had returned to relative normality after months with very few local cases.
More than five million people across Sydney will be subject to movement restrictions from Saturday evening.
The containment rules also apply to hundreds of thousands of others living in nearby coastal communities and the Blue Mountains towns that divide the city from Australia's farming hinterland.
"When you have a contagious variant, like the Delta virus, a three-day lockdown doesn't work -- if we're going to do this we need to do it properly," said Gladys Berejiklian, the premier of New South Wales state.
"We do need to brace ourselves for a potentially large number of cases in the following days," she added.
The lockdown had originally only applied to Sydney's business district and affluent eastern suburbs, but the fast spreading outbreak elsewhere pushed authorities to take a more drastic step.
In the Rocks, a historic precinct dating back to the first European settlement of Australia in the shadow of the Sydney Harbour Bridge, Chris Kriketos said he felt a "really bad case of deja vu".
"We've been struggling to get it back from the lockdowns of last year," said the 32-year-old, whose family bakery has been in the area for nearly four decades.
"Today just feels like another kick while you're slowly getting up."
- 'This is not over' -
To the east on Bondi beach, locals exercised on sunny winter's day as queues of cars poured into a drive-in Covid-19 testing clinic nearby.
"In the last few months, on a bad day in Australia, we had five or ten cases ... look overseas and they're in the thousands," Ron Gottlieb, 60, told AFP.
"We have been really blessed and it just shows that this is not over by any stretch of the imagination."
Health officials across the world have been alarmed by the rapid spread of the Delta variant first seen in India, with instances of people passing on the virus during fleeting encounters in shops and then quickly infecting close family contacts.
"The Delta variant is proving to be a very formidable foe," state health minister Brad Hazzard told reporters.
"No matter what defensive steps were taking at the moment, the virus seems to understand how to counter-attack."
Sydney's restrictions require people to stay home for at least two weeks, only venturing out to purchase essential goods, obtain medical care, exercise, go to school or if they are unable to work from home.
Anyone outside of the lockdown zone who had visited Sydney since Monday was also instructed to self-isolate for 14 days.
The city is experiencing the latest in a string of snap "circuit-breaker" lockdowns across major population centres around Australia, with most cases linked to returning travellers held in hotel quarantine.
Australia has been among the world's most successful countries in containing Covid-19, with just over 30,000 cases and 910 deaths in a population of about 25 million.