The strain, which is ravaging Britain and caused London to go back into lockdown, has been brought into NSW by two travellers from the UK.
The mutation is believed to be around 70 per cent more transmissible than earlier variants of the virus.
NSW chief health officer Kerry Chant said the state has had “a couple of UK returned travellers with the particular mutations” currently spreading through Britain.
However, she confirmed that the Northern Beaches cluster “does not have those mutations”.
British Prime Minister Boris Johnson announced on Saturday that the new strain had led to spiralling infection numbers.
His government tightened its COVID-19 restrictions for London and nearby areas, and also reversed plans to ease restrictions over the Christmas period.
The new variant in Britain has added a twist to a battle against the virus that many countries in Europe are waging.
The number of coronavirus cases in Britain surged by 35,928 on Sunday, the highest daily rise since the start of the pandemic, and it recorded 326 deaths, taking the official toll to more than 67,000.