Authorities have warned New South Wales could see up to 25,000 COVID-19 cases a day by the end of January as household contact rules are changed ahead of Christmas.
Health Minister Brad Hazzard said the "simple maths" of Omicron's 1.5 reproductive rate could cause a surge in infections next year after the state recorded 1360 new infections overnight, up from 840 yesterday.
"By the end of January, we could be looking at 25,000 cases of Omicron every day," Mr Hazzard said.
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"We may not get to 25,000 cases every day – but we could."
The modelling was based on outbreaks and analysis of Omicron cases in South Africa and the UK.
Mr Hazzard said NSW needed to be "on alert", as Omicron cases were "doubling every two to three days".
Vaccines were not stopping the transmission of Omicron, Mr Hazzard added.
"But it would appear the severity of illness is not as bad as it was with previous variants of the coronavirus," he said.
Dr Chant has urged NSW residents to limit their social activities to reduce the spread of the virus.
Dr Chant said people should still wear masks in public, even though it was no longer mandated.
NSW residents have been urged to get their booster vaccines amid the rise of Omicron infections.
"We do know boosters are critical at getting the immune response," Dr Chant said.
New close contact rules
Premier Dominic Perrottet has redefined the isolation restrictions for close contacts in the state.
Fully vaccinated close contacts will only need to isolate until they receive a negative PCR test, however, household contacts will still be required to isolate for seven days.
The changes aim to stop thousands of people from spending Christmas in isolation.
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NSW COVID-19 cases surge in past 24 hours
COVID-19 cases have surged in NSW as the state recorded 1,360 infections in the past 24 hours.
One person with the illness has died, but intensive care numbers did not see a significant spike, lifting from 20 to 24 patients.
The total number of the Omicron strain of the virus is now 110.
NSW Health said it remains concerned about the escalation in COVID-19 transmission in the Newcastle area.
Dr Chant said most of the cases in Newcastle appear to be Omicron.
More than 200 people who attended the Argyle House in Newcastle on December 8 have now tested positive to the virus.
Dr Chant said this outbreak shows that the Omicron variant has an "attack rate" of 30 per cent in venues.
Mr Hazzard told 2GB yesterday that a COVID-positive person from a boat party on Sydney Harbour, which sparked a cluster last week, ignored health advice to self-isolate and attended the Argyle House in Newcastle.
NSW Police is investigating the actions of this person, Mr Hazzard said yesterday.
Argyle House has announced on social media that the venue is closed until further notice as a result of the outbreak.
Anyone who went to the nightclub from 9pm on Wednesday, December 8 to 3am on December 9 has been deemed a close contact, must immediately get tested and isolate for seven days.
The Newcastle outbreak has also spread to Queensland after a plane from the steel city to the Sunshine State was declared a high-risk exposure site.
It's understood a passenger with COVID-19 travelled on a flight to Brisbane, before catching a connecting one to Townsville.
In Victoria, there were 1405 new cases, with three more deaths.
The NSW woman who died with the virus today had received three doses of a vaccine.
She was aged in her 90s and had underlying health conditions, NSW Health said.
The woman died at the Gillawarna Village Aged Care Facility in Georges Hall, where she acquired her infection.
This is the third death linked to an outbreak at the facility.
Concerns over easing of restrictions
The new jump in NSW came as the head of the NSW branch of the Australian Medical Association sounded a note of concern over the end of the state's mask mandate.
From today, masks are only required on public transport, in airports and on planes, and for front-of-house hospitality staff who are unvaccinated.
People are still "strongly encouraged" to wear masks when they cannot socially distance.
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It's one of a number of changes that come into effect across the state today, with the removal of virtually all remaining restrictions for vaccinated and unvaccinated people.
But NSW AMA president Dr Danielle McMullen said the rising case numbers were a worrying sign.
"We've been worried in the weeks leading up to this anyway, and encouraging the government to reconsider the mask mandate in particular," Dr McMullen told Today.
"We know that indoor masks are a really simple, cheap way of reducing the spread of COVID-19."
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She said people were likely to be nervous about getting infected ahead of Christmas, particularly with parties and gatherings on this week.
"I think the best thing we can all do, to be able to have as much of a normal life as possible, is to keep those masks on indoors, get tested if you even have the slightest sniffle, go and get a proper PCR test," Dr McMullen said.
"And if you're going to a big Christmas gathering or you're going to go visit nan or visit other elderly relatives, maybe think about doing one of the home tests before you go out, even if you are feeling fine, because we are seeing some spread from people who just don't know they're carrying COVID."
Despite recording 804 new COVID-19 cases yesterday, just 21 people were in intensive care – compared to more than 200 when NSW last topped 800 daily cases.
Dr McMullen said doctors were "cautiously confident" that Omicron appeared to be a milder variant.
"Our health systems are coping, but even if it's only a mild illness, we still can't afford to have the whole community infected all at once," she said.
