South Australia will enter an immediate six-day lockdown to curb the spread of a coronavirus outbreak discovered days ago.
The state has detected 36 cases since infections were found in Adelaide on Sunday, the first community cases detected in six months.
On Monday, as 17 cases were confirmed, officials had begun ordering thousands of suspected close contacts to self-isolate, and suspended international flights.
Adelaide residents have since been flocking to Covid-19 testing sites, with many forced to wait several hours in long queues to be seen by overwhelmed clinicians.
Authorities say the “circuit breaker” measures were necessary to stop the virus’ spread “at the beginning”.
Australia has previously also responded aggressively to small outbreaks.
Various state governments have at times closed parts of the economy, enforced border restrictions and other measures to stop the virus’ spread.
The lockdown, to begin at midnight on Wednesday, comes just weeks after neighbouring state Victoria beat a second wave, which caused about 800 deaths.
There would be a further eight days of lesser restrictions following the “six day pause”, officials said.
Almost immediately after the lockdown announcement, images on social media showed people queuing at supermarkets to buy toilet paper and other supplies.
Authorities had urged people to avoid panic-buying, confirming supermarkets and pharmacies would remain open.
Melbourne, which recorded thousands of cases and hundreds of deaths at the height of its outbreak, has begun easing restrictions after more than two weeks without any new cases.
Other regions, where the virus has largely been stamped out, have imposed new quarantine rules on anyone travelling from South Australia.
The country’s internal borders had been gradually reopening and were due to be almost fully reopened by Christmas.
Australia has been relatively successful in containing the virus, with just over 27,700 cases and 907 deaths recorded since the pandemic began.