Health authorities are working to investigate how a western Sydney man contracted COVID-19.

NSW Health's Dr Chatu Yapa said the infection is believed to be connected to the Berala BWS cluster but said investigations were still underway.

The man's infection was the only locally acquired case reported on Saturday as well as 11 others found in returned Australians in hotel quarantine.

The new cases bring the state's total number of confirmed cases to 4868, with 100 considered active and one person being treated in intensive care.

Dr Yapa said it was "very likely" COVID-19 continued to circulate throughout the community among people with mild to no symptom.

"It is vital that we pick up every case of COVID-19 if we are to prevent further community transmission, and the best way we have of doing this is maintaining high testing numbers," she said.

"Anyone who is experiencing any cold or flu-like symptoms, no matter how mild, is urged to isolate immediately, get tested and continue to isolate until a negative result is received.

"This is particularly important in areas where there have been recent cases, including western Sydney, south-west Sydney, the Northern Beaches and Wollongong."

There are more than 350 COVID-19 testing locations across the state.

There have also been 4,460,152 tests conducted in total. Of those, 14,547 were taken on Friday.

Originally published as NSW records one new COVID-19 case