Melbourne was ordered Wednesday to remain in lockdown for another week, as Australian authorities try to stamp out a quick-spreading coronavirus strain they described as an "absolute beast".
Five million city residents were hoping to exit a seven-day lockdown just before midnight Thursday, but those plans have been thwarted by the spread of the "Kappa" variant, which was found in India.
"We've got to run this thing to ground otherwise people will die," Victoria's acting state Premier James Merlino said, describing this strain of the virus as "quicker and more contagious than we have ever seen before".
Australia is battling to stop a cluster of 60 cases from growing in its second-biggest city, and to remain one of the few countries in the world without endemic transmission.
The border remains closed to most travellers -- with the exception of New Zealand -- and authorities are quick to impose restrictions when Covid-19 cases are detected.
But outbreaks in Taiwan and Japan have underscored how initial success containing the virus can quickly be eroded without widespread vaccination, and only about two percent of Australians have been fully jabbed to date.
Merlino said stay-at-home orders would likely be lifted for Victorians living outside Melbourne on Thursday, though a swathe of restrictions would remain, including caps on wedding guests and mourners at funerals.
Melbourne residents would largely be stopped from travelling outside the city, but senior school students will return to classrooms and some outdoor workers can return to their jobs, he added.
Brett Sutton, Victoria's chief health officer, said the Kappa variant was an "absolute beast" and said the extended lockdown would limit each person's contacts from about 100 others to just a handful.
"There are a dozen countries that had no community transmission going into 2021 that have now lost control, that have community transmission and will probably not bring it back to a point where they've got no community transmission again," he said.
Thousands of close contacts have been identified and the list of exposure sites has grown to about 350.
It is believed to be the 17th time in six months that the virus has leaked out of Australia's makeshift hotel quarantine facilities, which are now facing tough scrutiny.
Merlino urged the federal government to pay for a proposed purpose-built quarantine facility in Victoria and offer financial support for workers and businesses impacted by the state's fourth lockdown.
"Victorian businesses are absolutely devastated by this lockdown, as are our families and communities," he said.
But Prime Minister Scott Morrison has so far resisted the call, saying the state had already received billions in funding during the pandemic -- adding up to more than any other Australian region.
The country of 25 million people has recorded 30,000 Covid-19 cases since the pandemic began -- with a large portion in hotel quarantine.