NSW won’t “go backwards” in its COVID battle, despite the detection of another Omicron case, Premier Dominic Perrottet says.

Urgent genomic testing late on Wednesday afternoon confirmed a Cabramatta man was the latest in Australia to be diagnosed with the worrying virus variant.

It is the country’s seventh Omicron case – after six earlier infections in NSW and one in a repatriated traveller in the Northern Territory.

The man, aged in his 40s, returned to Sydney after six months in Nigeria last week. He arrived last Thursday, before extra quarantine requirements were imposed on travellers from Africa – and tested positive to COVID late on Tuesday.

“The reason he was tested is he does have symptoms. But I understand at this point they’re mild symptoms,” Health Minister Brad Hazzard said.

NSW Health said at least six people on flight QR908 from Doha to Sydney on November 25 are known to have been in southern Africa within 14 days of flying home.

“There is currently no evidence that transmission occurred on the flight,” it said in a statement on Wednesday afternoon.

“However, investigations into the five COVID-19 positive passengers on the flight, which includes two confirmed cases with the Omicron variant, are ongoing.”

The man spent several days in the community before his diagnosis. More exposure sites are expected, with one already announced – Chemist Warehouse at The Grove, from 8-8.15pm on Monday.

Mr Hazzard said the man had been “out and about” and urged NSW residents to be aware of any further health alerts.

NSW, which had another 251 COVID infections on Wednesday, has increased fines for people who fail to comply with quarantine and testing requirements from $1000 to $5000 as it tries to deal with the worrying variant.

But Mr Hazzard said the government was not considering another lockdown.

“As one who has delivered that news, bad news, to the community on many occasions, I feel like it’s time for a change in approach,” he said.

“We don’t know how many more variants of this virus are going to come.

“The challenge for us as a government and the other governments … is to strike a different balance to the ones we had in the past.”

Later, Mr Perrottet echoed Mr Hazzard’s caution.

“[I’m] getting asked questions here about six cases …. six cases … Let’s shift the thinking,” he said.

“The thinking needs to move away from every single day saying ‘here’s the case numbers’.

“It’s about the hospitalisations and the ICU numbers.”

NSW Health is also retesting coronavirus swabs from recent arrivals from southern Africa, to see if there are other earlier cases of the variant.

Anyone who has arrived in Australia from Africa in the past two weeks is asked to get tested for the virus.

“There was no awareness of Omicron until last Thursday or Friday, it seems like a lifetime ago already, but it was only a few days ago,” Mr Hazzard said.

Dutch health authorities said on Wednesday (Australian time) that they had found Omicron in COVID test samples dating from November 19 and 23. Previously, the first cases of the variant were thought to have arrived in the Netherlands on two flights from South Africa on Sunday.

When national cabinet met on Tuesday, the federal, Victorian and NSW governments agreed they were “not keen to see a return to lockdowns”.

At a special national cabinet meeting on Tuesday, federal, state and territory leaders examined data indicating Omicron is more transmissible than previous COVID-19 variants.

But there is no evidence it causes more severe illness, and not enough evidence to show vaccines and treatments are less effective against it.

UNSW epidemiologist Mary-Louise McLaws has urged people to be cautious over the next fortnight.

“We should be on high alert because there are many things we still don’t know about this particular mutation,” she told the Nine Network on Wednesday.

“We don’t know, of course, whether it gets around things like vaccine efficacy and let’s hope it doesn’t.

“I would advise that you just be highly cautious. You don’t want to get sick over the holidays. Wear your mask when you are shopping.”

Labor frontbencher Tanya Plibersek said no one wanted to see a return to widespread lockdowns.

“We need to do everything we can as a country to avoid that sort of social and economic hit. People are so tired of the lockdowns and the restrictions,” she told ABC radio.

“Whatever the medical advice tells us we need to do to keep Australians safe, we should do.”

Victoria had 1179 more cases and six more deaths on Wednesday.

-with AAP