New South Wales has entered its fourth COVID-19 wave after a sharp spike in new cases, Chief Health Officer Kerry Chant has warned.
There were 19,800 cases of COVID-19 detected in NSW in the seven days to 4pm yesterday.
It is a jump of 7,350 cases on the week before, when 12,450 cases were detected in NSW.
Dr Chant on Friday said surveillance data showed there were already high levels of community transmission of the virus.
"I can confirm we are entering the fourth wave of COVID," Dr Chant told ABC News.
"The wave is taking off with some trajectory, it will be quite a steep wave and hopefully the decline will be equally as steep.
"That's why it's important the community takes these protective measures now and I can't stress the urgency — if you're going to get vaccinated do it immediately."
There are 974 people currently in hospital with the virus in NSW, with 32 admitted to intensive care.
Dr Chant said modelling suggested the wave of new cases would start to subside by December.
"There is a sense that the wave may well peak before Christmas and we may be on the decline," she said.
"But the message is clear … this is an increased risk period for COVID so please now is the time to take those protective behaviours."
Premier Dominic Perrottet said it was inevitable NSW would face a fourth wave of COVID-19 over summer.
He said the onus was now on individuals to exercise personal responsibility if they test positive to COVID-19.
"If you're sick you stay at home, if you're not sick you go to work and you enjoy everything," he said.
"We need to live alongside the virus, it's not going away. I've been saying that for months.
"We always expected there to be an increase in cases over summer, that was the expectation from National Cabinet a few months ago."
The NSW Sewerage Surveillance report shows COVID-19 gene copy detections increased in Wollongong but fell in Quakers Hill, according to the latest weekly data.
Figures are not yet available for Bondi or Liverpool.
COVID-19 gene copy detections were also found to be on the rise in a number of regional areas including Gosford-Kincumber, Batemans Bay, Taree, the Hunter region, Tweed-Banora Point and Port Macquarie.
Epidemiologist Alexandra Martiniuk, from the University of Sydney, said the current wave was made up of a "super stew" of Omicron sub-variants, including two new strains BQ.1 and XBB.
"There's no sense that it's going to rip through the population causing great destruction," she said.
"However we do anticipate that a large number of people could get sick, with the kind of sickness where they need to stay home and off work."
Professor Martiniuk said high levels of vaccination and high rates of natural infection with COVID-19 meant this current wave would probably not be as severe as previous waves.
"We're in a much better place than we've ever been with the other waves," she said.
"The [new sub-variants] are known to evade immunity so transmission will increase, that means it's more infectious and more people will get it.
"But they're not known to be more severe in the disease that they cause."
