The number of people with COVID-19 being treated in intensive care units has increased in NSW, Queensland, Victoria, South Australia and the Northern Territory.
In NSW, where 29 deaths and 17,136 new COVID-19 cases were recorded on Thursday, there are 2,722 patients in hospital and 181 in ICU.
That's a drop from the 2,794 hospitalisations reported on Wednesday, but the number of patients in ICU increased by six.
Authorities have reiterated the benefits of vaccination rates, with one in two children aged five to 15 years unvaccinated.
The uptake of third doses among adults is moving slowly - from 29 per cent to 36 per cent in the past week.
NSW Health Deputy Secretary Susan Pearce said about 100,000 vaccination bookings went begging at state-run clinics last week, suggesting "a perception in the community that Omicron is milder" was to blame.
"What we know is that to prevent severe disease associated with COVID, that booster is absolutely critical," she said.
About seven per cent of NSW adults are either unvaccinated or have had just a single dose. They made up 31 per cent of the deaths reported on Thursday.
Victoria recorded 13,755 new COVID-19 cases and 15 deaths on Thursday.
The state reported 1,057 hospitalisations and 117 patients in ICU, down on 1,089 hospitalisations on Wednesday but up from 113 in ICU.
Premier Daniel Andrews said case numbers and hospitalisations were trending down and the state's chief health officer had flagged the Omicron outbreak may have peaked.
"If we see these numbers continue, we continue to see hospitalisations falling, there's certainly stability there," he told reporters.
Mr Andrews also announced that from this weekend, five- to 11-year-olds can walk up to receive a vaccine from some state-run hubs, in a bid to increase uptake before school's return on Monday.
The hubs include Sandown Racecourse, Dandenong Plaza, Caroline Springs Leisure Centre, Sunshine Hospital, Melton Vaccination Hub and Campbellfield Ford Complex.
Additionally, 15 primary schools will provide pop-up vaccination clinics this weekend, including in South Melbourne, Wyndham Vale, Lilydale and Fountain Gate.
Queensland recorded 15 deaths and 11,600 new COVID-19 cases, with hospital numbers falling by 60 to 829, but ICU admissions up by one to 48.
Responding to the fall in hospital admissions, chief health officer John Gerrard said: "Most of that fall has been on the Gold Coast ... so the Gold Coast has very clearly peaked and is on its way down.
"We believe that the greater Brisbane area, the rest of southeast Queensland, is approaching its peak right now."
Health Minister Yvette D'Ath said the latest hospital figures had her feeling optimistic.
"I haven't felt that way for a few weeks now, but looking at the numbers over the last 48 hours, seeing the drop in patient numbers, even our furloughed staff, we're just seeing a bit of a trend," she said.
Modelling had projected hospital admissions in the "multiples of thousands" at the peak of the wave, Dr Gerrard said.
"The reason why we are doing so well is because so many of the Queensland population were vaccinated before the virus was introduced," he said.
What's happening elsewhere?
Tasmania now has no one in ICU, a fall from two people yesterday, and the state has 5,026 active cases, continuing a downward trend from 19 January.
South Australia reported 13 deaths and another 1,953 COVID-19 infections, below the state's seven-day average for new cases.
Hospitalisations remained stable at 288 and the ICU number increased by one to 27.
The ACT has hit a record-level of hospitalisations with 73, but ICU admissions fell from five to four.
There were 626 new COVID-19 infections in the Northern Territory.
The number of patients in hospital with COVID-19 was 95, up from 84 on Wednesday, while ICU admissions increased from three to four.
The NT government also revised up Wednesday's case numbers after including more rapid antigen test results.
Health Minister Natasha Fyles says Wednesday's tally now stands at 778 and not the 492 originally recorded.
Ms Fyles said the government was comfortable with the level of hospitalisations, but remained concerned at low regional testing rates.
"We've stabilised those case numbers over the past couple of weeks, and that's really important in flattening that curve," the minister said.
"But overall, our testing rates in central Australia are pretty low. They were low yesterday.
"So while we're reporting just a handful of cases in communities, we really need people to come forward to be tested to remain confident that we are on top of things."
With additional reporting by SBS News.