The South Australian government has defended its decision to send residents into a hard lockdown despite low case numbers over the past few days.
Speaking on Sunday, Chief Public Health Officer Nicola Spurrier said modelling suggested the state had a 99 per cent chance of enduring a "significant" COVID wave if it did not enforce a lockdown and "supercharge" its contact tracing efforts.
Meanwhile, NSW premier Gladys Berejiklian told reporters on Sunday she would not have sent her state into lockdown if presented with the same information.
"Look, it's not for me to question what other states think or do ... but I wouldn't have shut down my state after having that information," Ms Berejiklian said.
Prof Spurrier showed a press conference graphs of the modelling, which she received last week as she decided how to deal with the emerging outbreak.
It showed there was a 50 per cent chance there would have been about 100 daily cases by mid-December and a smaller but "not negligible" chance that numbers would reach 200 per day.
"What we can say is that we absolutely were looking at facing a second wave," Prof Spurrier said, claiming she had "no regrets" about her decision.
The modelling was not distorted by false information provided to authorities about a pizza shop worker which suggested he had caught the virus from a surface, she added. The false information has been blamed for sending the state into lockdown.
South Australians emerged from the strict lockdown on Sunday to a softer set of restrictions.
Restaurants and pubs are back open, with bookings up to 10 allowed. Schools will reopen on Monday. Beauty salons and gyms are back as well.
Private gatherings of up to 50 people can go ahead as long as there is no more than one person per four square metres.
However community sport and recreation centres are still not allowed to operate and people are being encouraged to continue working from home for the next eight to 10 days if possible.
South Australians are urged to wear masks where they cannot physically distance.
The wisdom of the hard lockdown was thrown into question after authorities said a pizza worker had lied to contact tracers about his whereabouts last week.
Premier Steven Marshall said investigators spoke to the worker on Saturday and seized electronic devices from him.
The worker, 36, is believed to be in Australia on a temporary graduate visa.
Police will provide a comprehensive briefing on the pizza shop investigation on Monday, Mr Marshall said.
SA recorded just one new case on Sunday, a woman in her 20s quarantined in a hotel after travelling overseas.
The case was unrelated to the Parafield cluster in suburban Adelaide, which remained at 26 cases.
Despite the low numbers, Prof Spurrier said she would only be "fully confident" SA had escaped a second wave in a few weeks.
Police issued around 182 warnings and 103 fines in the past two days to people "blatantly" disregarding stay-at-home directions, Mr Marshall said.
There are 37 active cases, including a man in his 30s who is in hospital.
Nearly 17,000 tests were carried out on Saturday. More than 4000 contacts or close contacts of the outbreak remain in quarantine.