Although Adelaide’s outbreak had not yet met the Commonwealth’s definition of a coronavirus hotspot of 10 cases per day for three days, Professor Kelly said the lockdown had the support of federal health authorities.
“They know their system, they know their people, that is the decision they have made and we back them in terms of that decision,” he said.
The lockdown begins at midnight on Wednesday, with police set to enforce the strictest lockdown measures ever seen in Australia, including the closure of schools and hospitality venues and only one person per household allowed out of their homes each day.
“We need a circuit-breaker to stay ahead of this,” South Australian Premier Steven Marshall said, announcing the measures.
“We need breathing space for a contact tracing blitz to protect the elderly, to protect the vulnerable, to protect our entire community.”
Returning from a trip to Japan, Prime Minister Scott Morrison posted a message on social media in support of the lockdown.
“The establishment of a pre-emptive and temporary six-day lockdown to keep South Australians safe and stay ahead of the outbreak draws on lessons from earlier outbreak experiences,” he said.
“These are precautionary and temporary measures with a clear end date.”
The announcement of the lockdown was met with panicked scenes at South Australian supermarkets, as residents prepared for six days inside.
The head of South Australia’s retail union has implored the government to deploy police to protect the safety of shop workers, saying the announcement was “causing chaos”.
“There is a run on the shops,” said SDA state secretary Josh Peak, reminding shoppers supermarkets will remain open during the lockdown.
New venues were added to South Australian health authorities’ list of concern on Wednesday, including Woodville Pizza Bar in Adelaide’s inner north, where investigations determined a part-time worker had also worked as a security guard at Peppers hotel after he was identified as a close contact of a kitchen hand at the Stamford hotel who tested positive.
Anyone who received a takeaway delivery from the venue between the November 6 and November 16 has been asked to self-quarantine and get tested.
Asked why hotel staff had been working elsewhere, South Australia Police Commissioner Grant Stevens said restrictions on this would be “difficult to impose”.
“We cannot quarantine people simply because they are assisting us in working in quarantine hotel,” he said.
Australian Council of Trade Unions secretary Sally McManus said a solution for casual and contracted workers working in high-risk environments as well as other jobs would “save lives in the process”.
“We’ve seen around the country through this crisis that insecure work is a risk to public health,” she said.
After some other states imposed travel bans earlier this week, NSW issued advice on Wednesday to avoid unnecessary trips until the Adelaide COVID-19 outbreak is under control.
Premier Gladys Berejiklian said arrivals from Adelaide would now be subject to surveillance checks to ensure they had not been to any areas where they may have been exposed to an infectious person.
“If you don’t have to go there in the next few days, delay your travel,” the Premier advised NSW residents.
“The borders are completely open but if it’s non-essential travel, think about whether you want to go in the next few days.
Mary Ward is a health reporter at The Sydney Morning Herald.
Josh Dye is a news reporter with The Sydney Morning Herald.
Nick Bonyhady is industrial relations reporter for The Sydney Morning Herald and The Age, based between Sydney and Parliament House in Canberra.