It comes as the district recorded 424 cases of COVID-19 on Wednesday, most of which Hunter New England Health public health physician Dr David Durrheim said were expected to be the "highly transmissible" Omicron variant.

More than half of the local cases (243) were from Newcastle, 76 were from Lake Macquarie, 69 were found in Maitland, Port Stephens had 18, there were seven from Cessnock, four in Mid Coast, two each in Moree Plains, Singleton and Tamworth and one in Armidale.

There are currently 827 active cases in the district, seven of which are in hospital, and three in intensive care.

The 424 cases made up about a third of the state's overall infections for the 24 hour reporting period to 8pm Tuesday, and were a jump of 200 on the day before.

Dr Durrheim said genome sequencing had confirmed two cases within the cluster are Omicron, and believed the majority of recent cases would be the same variant.

"Which we have seen is highly transmissible, particularly in crowded settings," he said.

"Fortunately most people who've been double vaccinated or even had a booster have had very mild illness."

The spike in cases comes as the state wound back restrictions, including for the unvaccinated, with mask wearing limited to only public transport and planes, at airports, and for indoors front-of-house hospitality staff who are not fully vaccinated.

However Dr Durrheim said he urged people to "be sensible".

"With the relaxation further of state restrictions we can probably expect to see even further cases across Hunter New England but also across the state," he said.

"So we need to be sensible. Even though we don't have to wear a mask it's a jolly sensible thing to wear a mask when ever you're in a setting where you can't distance yourself from others and particularly indoor settings.

Dr Durrheim said NSW Health remained concerned about the scale of COVID-19 transmission at The Argyle House nightclub and Finnegan's Hotel in Newcastle and in the community since. He said many of the confirmed cases did attend other gatherings including pubs, clubs and Christmas events.

More than 150 of the 650 people who attended the Argyle House nightclub on the Wednesday night have since tested positive to COVID-19, with more cases expected.

"We are aware that at least six people were present at the Finnegans Hotel while infectious, and more cases are expected to arise from exposures at this venue," he said.

Hunter New England Health has enacted temporary visitor restrictions at hospitals and health facilities across the Newcastle, Lake Macquarie and Lower Hunter regions in response to the outbreak.

A maximum of one visitor per patient per day will be allowed into these facilities. Exemptions will be considered on a case-by-case basis for compassionate or extenuating circumstances such as those in a critical condition, receiving palliative care or visiting a new sibling.

All visitors to all facilities across the district must pass a screening process prior to entry. Those who are unwell or with cold or flu-like symptoms, who have been tested for COVID-19 and are awaiting results or known to have visited an exposure site, will be asked to reschedule their visit.

All visitors must be double-vaxxed, wear a surgical mask, check-in via the QR code on-site, follow hygiene protocols and maintain social distancing.

"These measures are in place to protect our patients and visitors, as well as our staff who continue to provide quality of care during this peak period," Dr Durrheim said.

"We know this is challenging, however the safety of patients, staff and visitors is paramount. We thank the community for their understanding and patience, and we will continue to keep them informed of any further updates."

NSW recorded 1360 cases on Wednesday, with Hunter New England claiming the highest number of cases of all health districts.

There were 195 case in South Western Sydney, 174 in South Eastern Sydney, 162 are from Western Sydney, 115 are from Sydney, 100 are from Northern Sydney and the Central Coast had 49.

Premier Dominic Perrottet, Minister for Health Brad Hazzard, NSW Chief Health Officer Dr Kerry Chant and NSW Health Deputy Secretary Susan Pearce will provide a COVID-19 update at midday.

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