Premier Gladys Berejiklian said people who test positive to the strains while in quarantine "will have to start the 14 days from the onset of symptoms".
Authorities have advised people to stay at home due to COVID-19 cases.
With Sydney fireworks restrictions and other rules, seeing in 2021 will be a quieter affair – but maybe, after everything, that’s a good thing.
Here's the limit for each household as authorities try to get the Northern Beaches cluster under control.
NSW recorded seven new cases on Tuesday linked to the Avalon cluster.
States and territories have moved fast to update border bans, ruining many people's Christmas travel plans.
“We're extremely concerned,” NSW Premier Gladys Berejiklian said on Friday as she confirmed outbreak is an "international strain".
The NSW premier took a COVID-19 test last week, but didn't self-isolate till she received the result.
"I feel for Indigenous Australians who don’t feel the national anthem reflects them and their history," said the NSW premier.
Bill Shorten has empathised with the NSW Premier.