New South Wales has reported 52 new COVID-19 deaths on Sunday, its highest daily number of the pandemic, while Victoria posted 20 and Queensland recorded 13 fatalities.
South Australia reported two deaths, while Tasmania reported one.
There were no deaths recorded in Western Australia, the Australian Capital Territory or the Northern Territory.
In NSW there were 13,524 cases reported, while the number of people in hospitals continued to decline to 2,663, a fall from 2,693 on Saturday and 2,737 on Friday.
The number of people in ICU in the state was 182, a decline from 186 the previous day.
Hospitalisations in Victoria on Sunday sat at 889, a drop from 953 a day earlier, and 988 on Friday.
There were 10,589 COVID-19 cases reported in Victoria on Sunday and 111 people in ICUs, which also signalled a decline from 114 on Saturday.
The figures come after COVID-19 Commander Jeroen Weimar said on Saturday that authorities had detected "literally a handful" of cases with the Omicron sub-variant, which has been dubbed 'son of Omicron'.
"We're obviously following the international developments on the BA.2 sub-variant of Omicron closely," he told reporters in Melbourne.
The state's seven-day case average stands at 12,659 infections, a considerable drop from the previous week's figure of 19,000.
Mr Andrews says the trend, along with a reduction of more than 100,000 active cases across Victoria over the same period, paints "a more optimistic picture than even our modelling predicted".
Health authorities announced 10,589 new cases on Sunday morning, while Mr Andrews says the state is currently managing about 78,000 active infections in total.
It comes as Queensland also reports a downward trend in hospitalisations.
There are 745 patients in hospital and 41 people in intensive care across the state - down from the 818 hospitalisations and 54 ICU admissions reported on Saturday.
Queensland also reported 1,580 new infections, including a case of the "son of Omicron" sub-variant.
Meanwhile, South Australia reported a slight increase in hospitalisations, with 289 patients in hospital - up six from Saturday.
The state also posted 1,633 new infections of the virus.
The Northern Territory reported 849 new COVID-19 cases on Sunday, with the number of people in hospital rising to a new peak of 121. Of those, eight are on ventilators and three are in ICU.
Chief Minister Michael Gunner announced that from Tuesday, interstate arrivals will no longer need to take a rapid antigen test, nor will they be required to use the G2G app, though they will still need to complete a border entry form.
Unvaccinated travellers remain unable to enter the NT without an exemption.
Mr Gunner also announced that seven-day "lock-ins" would come into effect in a number of remote communities from 2pm on Sunday.
These lock-ins would affect the communities of Milingimbi, Milikapiti, Ampilatwatja, Palumpa and Elcho Island including Wessell and Galiwin'ku islands.
He said police would monitor transport in and out of these communities, with all non-essential road transport to stop, while warning that breaches could see fines of more than $5,000.
"Given the difficulties in stopping the spread of Omicron within a community, our priorities now have to be on ensuring we can limit spread between communities and focusing our efforts on caring for sick people, rather than using up manpower and hours and forcing stay-at-home orders for people who aren't sick or who aren't high risk," Mr Gunner said.
Tasmania recorded one death and 594 new cases in the latest reporting period.
There are 20 people in hospital in the state - up three patients from Saturday - and one patient in ICU.
The Australian Capital Territory has posted zero deaths and 584 new infections of COVID-19.
The territory has 62 patients in hospital, of which three are in intensive care and one is on a ventilator.
That's one more person in hospital than the previous day but two fewer patients in ICU.
Twenty new cases of the virus were reported in Western Australia on Sunday, with one patient receiving care for COVID-19 in hospital.
With AAP
