Rueful authorities in Melbourne announced a sixth lockdown for the city and Sydney reported a record number of new coronavirus cases Thursday as Australia faltered in efforts to bring a virulent Delta outbreak to heel.
Victoria premier Dan Andrews said he had "no choice" but to make the "very difficult announcement" to lock down Melbourne and the rest of the virus-weary state little more than a week after the last lockdown ended.
"None of us are happy to be here, none of us," he said, citing the danger posed by eight "mystery" cases that have yet to be traced.
"There is no alternative to lockdown" he added.
"The alternative is we let this run that gets away from us, and our hospitals will be absolutely overwhelmed. Not hundreds of patients but thousands."
When the Victoria lockdown begins at 8 pm (1000 GMT), more than half of Australia's 25 million population will again be in lockdown.
Six weeks ago, Sydney residents were ordered to stay home. But the measures have had mixed success in curbing the spread of the virus among a largely unvaccinated population.
On Thursday, the number of new infections in New South Wales state grew to 262, the largest daily tally since the pandemic began.
Health officials said almost all the new cases were in Sydney, but a handful of infections in other districts prompted state premier Gladys Berejiklian to widen stay-at-home restrictions to neighbouring areas.
Five positive tests in Newcastle -- a coastal city of 320,000 people north of Sydney -- prompted authorities to shutter schools and tell residents to stay home for at least a week.
Five people in their 60s-80s have died in Sydney in the past 24 hours, none of whom were fully vaccinated.
"I cannot stress enough how it's so important for everybody of all ages to come forward and get the vaccine," Berejiklian said.
Barely 20 percent of Australians have been fully vaccinated, thanks to an acute lack of supply and pockets of vaccine hesitancy.
- Under the gun -
Until now, Australia has dodged the worst ravages of the pandemic through a "Covid-zero" strategy of closing borders, mandatory travel quarantine, and aggressive testing and tracing.
But those tools appear blunted in the face of the Delta variant, which is much more transmissible than previous strains.
Since a Sydney driver was infected with Delta by an international flight crew in mid-June, New South Wales has recorded 4,319 locally acquired cases and clusters have popped up across the country.
Prime Minister Scott Morrison has vowed to ramp up vaccine deliveries by the end of the year, but stressed the need for cities to lock down to contain the spread.
"The virus doesn't move by itself. People staying at home ensures that the virus doesn't move," he said Thursday.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)