The number of people diagnosed with the Omicron variant of COVID in NSW has risen to 42, as the state orders anyone at a popular nightclub last week into isolation.

That’s eight more cases of the variant on Thursday, as total infections across NSW surged for a second day, reaching 420.

NSW Health is also concerned about a new cluster that has emerged from a trivia night at a Sydney pub. The pub patrons were diagnosed after the trivia night at the popular Oxford Tavern in Petersham on November 30, Sydney Local Health District said.

On Thursday, there was an alert for a night club at Byron Bay on the north coast, where thousands of teenagers are celebrating ‘schoolies’.

Anyone who was at Woody’s Surf Shack Night Club on November 30 or December 1-3, between 8pm and 3.30am is being contacted.

Anyone who is not fully vaccinated is considered a close contact and anyone who is fully vaccinated is considered a casual contact.

The nightclub alerted patrons to the exposure in a Facebook post. Photo: Facebook

NSW has 93 per cent of adults fully vaccinated for COVID-19 – just two per cent short of the goal nominated by chief health officer Kerry Chant.

The first dose tally for people 16 and older is just shy of that target – 94.7 per cent.

The new cases of the virus were recorded from 84,883 tests in the 24-hours until 8pm on Wednesday night.

There was one more death, a fully vaccinated man in his 70s with underlying health conditions from Lake Macquarie who died at Gosford Hospital.

Nearly 82 per cent of the state’s teens aged 12-15 have had one jab, while 77.4 per cent have had two doses.

There are 151 people in hospital with COVID, 25 of them in ICU and eight of them are ventilated.

No Omicron cases have been admitted to hospital in NSW for treatment of COVID-19.

Meanwhile, health authorities say anyone who attended the Oxford Tavern on the night of November 30 is considered a close contact, must get tested immediately and self-isolate.

Patrons who were fully vaccinated can come out of isolation if they have had a negative test on or after December 6, but will need to have another test on Sunday.

“If you have not been fully vaccinated, please remain in isolation until December 12, and have another test on this date,” Sydney Local Health District said.

The outbreak comes a day after Dr Chant attributed a spike in daily cases numbers to increased transmission in large venues such as pubs, clubs and parties as people began socialising freely again.

NSW Health is also trying to track down 140 people who signed into a Cadman Cruise on Sydney Harbour on Friday night, after five cases were linked to the event.

At least two are suspected to involve the Omicron variant.

Dr Chant said transmission was “predominantly occurring in vaccinated individuals” who experienced mild symptoms.