NSW Health has detected a likely sixth case of the Omicron COVID-19 variant, as the premier urges the public not to panic.
Initial testing strongly indicated another overseas traveller - who recently returned to Sydney from Africa - has the new variant of concern, NSW Health said.
The man in his 40s, who had spent six months in Nigeria, tested positive to COVID-19 on Tuesday and is fully vaccinated.
But Premier Dominic Perrottet is calling for calm, saying Omicron "was always going to get here".
"We're getting asked questions here about six cases - six cases," he said on Wednesday.
"Let's shift the thinking ... It's not about the case numbers. It's about the hospitalisations and the ICU presentations."
Health Minister Brad Hazzard said the latest suspected case flew into Sydney on Thursday on flight QR908 from Doha - the same flight as the Central Coast woman who was the fifth case.
The man, from Cabramatta in Sydney's southwest, has been circulating in the community and there will be a list of exposure sites from NSW Health later.
"The reason he was tested is he does have symptoms. But I understand at this point they're mild symptoms," Mr Hazzard told reporters.
When confirmed, the new infection will bring the total number of Omicron cases confirmed in NSW to six.
Mr Hazzard said the government was not considering another lockdown.
"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."
When national cabinet met on Tuesday the federal, Victorian and NSW governments agreed they were "not keen to see a return to lockdowns".
Restrictions will instead be "tailored" if a there are health concerns, Mr Perrottet said, with the next stage of the state's roadmap out of lockdown due on December 15.
A fully vaccinated woman in her 30s became the state's fifth confirmed Omicron case on Tuesday, and unlike the previously announced cases she had visited a number of venues on Friday and Saturday last week.
Two others on the woman's Thursday flight from Doha have also since tested positive, and neither had been in southern Africa.
The woman is isolating at home on the Central Coast and will not be fined because she arrived before new mandatory quarantine came into effect.
Things changed on Saturday, when federal health minister Greg Hunt announced people arriving from South Africa, Lesotho, Botswana, Zimbabwe, Mozambique, Namibia, Eswatini, Malawi and the Seychelles are required to enter hotel quarantine for two weeks.
The other four people confirmed to have the Omicron variant are in special health accommodation.
NSW now also requires all international arrivals be tested and isolate for 72 hours at a nominated address or accommodation.
On Wednesday, the penalty for non-compliance with isolation, testing and quarantine requirements increased from $1000 for individuals to $5000, and doubled from $5000 to $10,000 for corporations.
The state recorded 251 new cases of COVID-19 and no deaths in the 24 hours to 8pm on Tuesday.
Some 94.6 per cent of people 16 and older have had one vaccine dose, while 92.5 per cent are fully jabbed.
More than 81 per cent of teenagers aged 12-15 have had one vaccine dose, and 76.7 per cent have had both.
The emergence of the new variant has also seen the number of people getting booster shots increase by 40 per cent, Mr Hazzard said.
Australian Associated Press