South Australia has recorded one COVID-linked death and 1,723 new cases, as students begin to return to school.
SA Health said the death was a man in his 80s.
The state has 233 people in hospital — 40 less than the day before — including 21 in intensive care, with five on ventilators.
The case numbers increased by more than 450 on the day before, but Premier Steven Marshall said hot weather was to blame as testing sites closed and samples were not processed until yesterday.
Despite the numbers, Mr Marshall said he was hopeful South Australia was past the peak of the Omicron outbreak.
The state now has 18,741 active cases, down from the peak of around 35,000 last month.
Classes have resumed today, with an estimated 35 to 40 per cent of students learning at school and the rest due back in a fortnight.
SA Chief Public Health Officer Professor Nicola Spurrier told ABC Radio Adelaide this morning that returning to school was "a safe thing to do".
"Our modelling does show that we expect to have increases in paediatric admissions, but it's not a high number, and so we're expecting to have a little blip," she said.
"But we're still overall expecting to have our numbers decrease every day over this period of time."
Professor Spurrier said 1,317 of today's positive results came from PCR tests, while 406 came from rapid antigen tests.
Today also marked the transition of all year sevens from primary school to high school, bringing the state in line with the rest of the country.
Ethan Palmer, 13, started his first day of high school today at Riverbanks College, the new birth to year 12 school in Angle Vale, north of Adelaide.
He said he was "really excited, happy and also nervous" about returning to school.
Essential workers Michele and Joe Locampo also sent their two children back to school today.
Mrs Locampo, a nurse, said she was "pretty happy" with the situation.
"I'm not worried — COVID is here — so we've just got to live with it and try to normalise things," she said.
Mr Locampo said he felt comfortable that the benefits of his children returning to school outweighed the risks.
"The thing is you've got to interact with people and so they've been vaxxed as well, so we've done all the precautionary steps and it's up to them to be very careful and ultra-cautious," he said.
Their son, Massimo, said it would be "a bit weird" at school with most students not returning for another two weeks.
"I guess it'll be kind of be weird for not everyone to be there," his sister, Selena, agreed.
But not all parents have been happy with the state government's approach.
ABC Radio Adelaide caller Brooke, from Victor Harbor, said it was "of great concern" that some students in her son's reception class could not be vaccinated against COVID-19, even if their parents wanted them to be.
Children aged five to 11 became eligible for vaccination last month, but some students start reception at age four.
"Even my four-year-old understands the ludicrousy of the situation," Brooke said.
"I asked him what he felt about going to school and he said 'Mum but I'm not vaccinated'."
Education Minister John Gardner said there were no plans to extend at-home learning past the middle of February.
However, the Pitjantjatjara Yankunytjatjara Education Committee has announced schools in the remote Anangu Pitjantjatjara Yankunytjatjara (APY) Lands will return on February 16 due to COVID-19 outbreaks in the region and flooded roads.
Mr Gardner said he understood the "disruption" that families were facing, as parents struggled to follow the government's staggered approach to returning to workplaces at the same time as needing to supervise at-home learning for their children.
"But it's a week-and-a-half whereby these arrangements are in place; if you are unable to provide suitable supervision at home, then we have provisions for our schools to provide that supervision," he said.
Mr Gardner said all schools and childcare centres should have received their allocation of rapid antigen tests today, after about 50 facilities — mainly private childcare centres — started the week without them.
"I'm very confident that will be sorted out today for any individual sites with any individual circumstances," he said.
Opposition education spokesman Blair Boyer said the government had not prepared properly for school starting with RAT kits not available yet at all childcare centres and preschools and ventilation only being addressed hastily before the start of school.
"The government had months and months to get this right," he said.
"They buried their head in the sand."
