Instead, Premier Dominic Perrottet is urging people to come forward for their booster shots and take personal responsibility.

The state again broke the record for the highest daily case tally in any Australian jurisdiction on Sunday, when it reported 2566 new COVID-19 cases.

Mr Perrottet said on Sunday health authorities will monitor the situation, but it was "incredibly positive" that intensive care presentations have so far held steady.

"Now is our time as a state to stand tall and we can do that because of the efforts and sacrifices that people have made," he said.

There are 28 people in ICU wards around the state with the virus. That number has hovered in the mid-20s since late November.

The ICU population is the "key metric" for NSW, said Mr Perrottet.

"It's a time for calm, but it's also an important time to go out and get your booster shot because vaccination has been key to NSW's success," he said.

The majority of ICU patients continue to be people who are unvaccinated or who've received only one shot of the COVID-19 vaccine.

NSW residents are responding to the call to "join the booster club", as Health Minister Brad Hazzard put it on Sunday.

The state's health practitioners administered 15,000 doses of the booster shot last week - a number that has now almost quadrupled to 57,000 this week.

NSW Health is aiming to double that number next week.

Mr Hazzard again urged the federal immunisation advisory body to bring forward the booster shot interval from five months to three or four months.

The new cases were diagnosed from more than 148,000 tests processed in the 24 hours to 8pm on Saturday.

The premier acknowledged the long queues and wait times caused by the huge demand for PCR tests.

Health authorities are no longer doing genomic sequencing to discover what variant patients have, but are presuming the majority of new cases are the new Omicron variant.

It's not yet known what kind of severity of illness the highly transmissible variant can cause, said Deputy Health Secretary Susan Pearce on Sunday.

"The numbers are one thing but the severity will be the thing that makes the difference and that is at this stage unknown," she said.

While international counterparts are reimposing restrictions, and in some cases lockdowns, in response to the Omicron threat, Mr Perrottet said personal responsibility was key.

Sunday's case tally is up 84 from the previous day's total.

No new deaths from the virus were reported on Sunday.

Some 227 people are in hospital with the virus, up from 206 the previous day.

Some 93.4 per cent of people aged 16 and over in NSW are now fully vaccinated, while 78.1 per cent of those aged 12-15 are double dosed.

The state is nearing 95 per cent first-dose vaccination for 16s and over, reaching 94.9 per cent on Friday.

Australian Associated Press