NSW will be taking a multi-pronged approach to combatting a highly infectious UK variant of COVID-19, which has forced England into lockdown.
Chief Health Officer Kerry Chant said there was no single solution for travellers entering Australia after the strain was detected in returned travellers.
The British variant is believed to be up to 70 per cent more infectious than the original.
British Prime Minister Boris Johnson has ordered England into a new national lockdown until at least mid-February.
Australia has so far identified five cases of this particular strain in arrivals from the UK, including two in NSW, two in Victoria and one in South Australia.
Ms Chant on Tuesday said there was “no one silver bullet” to keep the community safe from variant viruses which are moving across the world.
“Just because you’re tested a couple of days before you get on the plane, you can develop the infection on the plane, you can develop as you’re getting off the plane, or the next day,” she said.
“It is about that universal approach, making sure we treat anyone with COVID as highly infectious and making sure we go through all of the end to end chains to ensure that we don’t have any incursion events in our community.”
Acting Premier John Barilaro said measures would always be put in place to protect Australians.
“We’re learning, like any other nation, there’s no playbook or rule book that shows you how to manage a global pandemic at the scale we’ve seen,” he said on Tuesday.
Ms Chant said she had been in contact with other countries to assess how variants are affecting immune-compromised patients.
“Clearly, there’s concerns of this emergence of strains, not just from the UK, but in other parts of the world, that may be associated with increased transmissibility,” she said.
“Recognising the rate of disease internationally is increasing, so the threat level is never higher than at the current time,” Ms Chant said.
Another international strain – a South African variant – was detected in a woman who arrived in Queensland on December 22 who went straight into hotel quarantine.
More than 30 countries around the world have recorded cases of the South African or UK coronavirus variants, including the US, Lebanon, Singapore, Pakistan, India, South Korea, Japan, France, Germany and Italy.
The World Health Organisation is yet to determine whether the new variants could undermine COVID-19 vaccines being rolled out around the world.