NSW has 31 cases of the new Omicron variant after recording 260 new cases of COVID-19 and two deaths.
NSW Health is still investigating the source of infection of a cluster of Omicron cases at Regents Park Christian School, St Peter Chanel Catholic Primary School in Regents Park, and the Sydney Indoor Climbing Gym in Villawood in southwest Sydney.
Genome sequencing on Monday found an additional six cases in the cluster, bringing the number of cases linked to the cluster to 20.
NSW Health said the original source of the cluster was believed to be a returned overseas traveller, who arrived in Sydney from Doha on flight QR908 on 23 November.
The traveller had spent time in Nigeria.
The number of Omicron cases in NSW acquired either overseas or on an international flight was 11.
NSW Health says none of the people infected with the Omicron variant has been admitted to hospital since the first case was recorded last week.
Among the latest deaths was a fully vaccinated woman in her 90s from western Sydney who died at Westmead Hospital.
She was a resident of the Blacktown Terrace Care Community aged care facility, where she acquired her infection - the first death linked to an outbreak at the facility.
An unvaccinated man in his 90s from southwestern Sydney died at Liverpool Hospital.
There are 155 COVID-19 patients in hospital, 28 of them in intensive care and five are ventilated.
There were 58,706 COVID-19 tests reported in the 24-hours to 8pm on Monday.
The adult vaccination rate is increasing slowly, with 94.7 per cent of those 16 and older having had their first dose, while 92.8 per cent have had both.
NSW Chief Health Officer Kerry Chant said the numbers were "inching incredibly slowly upwards towards our aim of getting that 95 per cent double-dose vaccination".
More than 81 per cent of teens aged 12 to 15 have had one vaccine dose and 77.2 per cent are fully jabbed.
Dr Chant urged parents to use the summer holidays to get teens vaccinated, saying "It will be really important to have those high vaccination coverages going into next year".
Dr Chant warned cases of the new variant would continue to climb.
"It is expected that our numbers linked to this cluster will rise as further results are confirmed," she said on Monday.
Three new Omicron cases recorded in ACT
Three new cases of COVID-19 linked to the Omicron variant have been detected in the ACT.
It takes the number of Omicron cases in the national capital to five.
Of the new cases, two are household close contacts, while the third is a casual contact.
Despite the arrival of Omicron cases in the ACT, Health Minister Rachel Stephen-Smith said the territory government was not looking to immediately implement further restrictions
A return to masks for indoor settings may also be considered.
"We are putting on hold consideration for the further easing of restrictions," Ms Stephen-Smith told ABC Radio on Tuesday.
"We might move to (indoor mask wearing) but no decision has been made on that."
However, due to Omicron cases, close contacts and household contacts will still need to undergo 14 days of quarantine, regardless of their vaccination status.
"It's about taking a precautionary approach, where there's so much uncertainty and making sure we're continuing to protect the community," Ms Stephen-Smith said.
Victoria records 1,185 COVID-19 cases, seven deaths
Victoria has recorded 1,185 new COVID-19 infections and another seven deaths, taking its toll from the pandemic to 1385.
The health department confirmed on Tuesday the state is managing 13,050 active cases, dropping from 16,503 on Monday.
There are 297 patients in the state's hospitals, 102 of whom are in intensive care and 25 requiring ventilation.
The seven-day hospitalisation average sits at 295.
Testers processed 52,257 results on Monday, while 3769 people were vaccinated in state-run hubs.
More than 91 per cent of Victorians over 12 are fully vaccinated.
Queensland has recorded one new locally-acquired case of COVID-19 as it prepares to open its borders and mandate vaccines in high-risk settings and venues.
Health Minister Yvette D'Ath says the new case emerged after 12,468 tests in the 24 hours to 6.30am on Tuesday.
The case is a man on the Gold Coast who is linked to three existing cases in the city and may be the index case as he is recently travelled to NSW.
Meanwhile, the minister said a flight to Cairns had been listed as an exposure site for Friday morning because an international traveller had flown there from Sydney and into hotel quarantine.
