Victorian authorities are investigating two more suspected Omicron cases, as they issued an urgent alert for anyone who has been to Melbourne Airport in recent days.

The state health department said it was investigating two more positive COVID tests with the S gene dropout – a signature of the Omicron variant.

That brings the total of community cases in Victoria thought to be Omicron to four. Thursday’s cases are in Melbourne’s west – in the local government areas of Brimbank and Wyndham – and come after two in Brimbank and the south-eastern council area of Casey on Wednesday.

“At this stage, it is known that three of these cases are not linked to international travel and their source of acquisition is under investigation,” the health department said.

There have also been positive wastewater detections for the variant at Melbourne Airport. The samples were collected on on December 1-2 and are consistent with a known suspected case of the Omicron variant who visited the airport.

“Anyone who works at or has visited Melbourne Airport is urged to watch for the mildest of COVID-19 symptoms and get tested as soon as possible if symptoms develop,” the department said.

Health authorities are interviewing all the suspected cases and have sent contacts into quarantine for seven or 14 days.

Victoria also has a confirmed case of the Omicron variant, in a fully vaccinated traveller in hotel quarantine.

The state had 1232 virus cases and a further nine deaths on Thursday.

Premier Daniel Andrews reiterated the state was not chasing an “Omicron zero strategy”, describing it as unachievable and not the “smart thing to do”.

“This thing is in our country and will be more widespread than any surveillance will show you,” he sid on Thursday.

“That’s just the nature of this virus. There’s always more cases than you know about.”

While health experts are trying to learn more about the variant since it was observed in South Africa, Mr Andrews noted early evidence suggested it was milder than the Delta strain and current vaccines were not compromised.

He had received no health advice to reimpose restrictions to quell an Omicron outbreak, akin to those announced in Britain.

“They’re having to have conversations about lockdowns and conversations about all sorts of things because they’re at 60 or 65 per cent double dose, not 95 per cent double dose,” he said.

Of Victorians aged 12 and over, 94.1 per cent are partially vaccinated, while 91.8 per cent have had two doses.

NSW Health has issued a COVID alert for Woody’s Surf Shack Night Club in Byron Bay, for several days last week.

Nightclub, pub alert in NSW

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 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 nightclub at Byron Bay on the NSW north coast, where thousands of teenagers are celebrating ‘schoolies’.

“We have just been alerted by NSW Health that a person who is a confirmed case of COVID-19 visited Woody’s Byron Bay on Saturday, December 4, while potentially infectious,” Woody’s Surf Shack Night Club wrote on Facebook late on Wednesday.

“We … have been advised that NSW Health will contact anyone who attended the venue at the same time with further instructions. If you were at our venue on this day and have any symptoms please go get tested.”

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.

NSW Premier Dominic Perrottet said the state government was closely monitoring the spread and severity of the Omicron variant. He did not expect delays to NSW’s plan to lift restrictions next week.

“Ultimately, let’s look at the position we’re in today,” he said.

“There are 420 cases, we have low hospitalisation rates … and there are a small minority of people who haven’t [been vaccinated].”

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.

NSW will largely scrap mandatory masks next week, while QR code check-ins will also be scaled back.

-with AAP