"We are managing to keep the rate of community transmission very low in NSW with just one [case] overnight," she told reporters on Thursday.

The single local case was recorded from 15,329 tests in the 24 hours to 8pm on Wednesday, - slightly up from 14,932 the day before, while six people in hotel quarantine were also diagnosed.

Ms Berejiklian said while the community transmission rates were low, she was disappointed that mask-wearing had declined on Sydney's public transport.

"If we see mask-wearing goes back up, we can increase the number of people who can use public transport.

"We won't have the confidence to do that unless more people are wearing masks," she said.

"We desperately need it to go back up."

NSW Deputy Chief Health Officer Jeremy McAnulty said the new locally acquired case was a close contact of a previously confirmed case in southwest Sydney, linked to the Liverpool private clinic cluster which now numbered 13.

Meanwhile, a coronavirus alert was issued for anyone who attended the Bathurst 1000 motor race last weekend after COVID-19 traces were found in the city's sewage.

NSW Health urged anyone in Bathurst to get tested even if they had mild symptoms of the virus and to remain in isolation until test results came back.

"NSW Health is urgently undertaking investigations, which include reviewing lists of all those known to have had the virus who attended or worked at the race," it said on Wednesday night.

NSW Health also wants people in southeastern Sydney to watch for symptoms of COVID-19 after a person who was in the area on October 15 tested positive.

"These investigations have now revealed this case may be linked to a person who NSW Health has identified as someone who likely had unrecognised COVID-19 infection during September and has since recovered," Dr McAnulty said.

Several venues have now been identified as places of potential exposure including Souths Juniors Club at Kingsford, Century 21 Dixon Real Estate, in Kingsford and The Shed Cafe at Royal Randwick Shopping Centre.

The alert comes as a swathe of COVID safe restrictions are being lifted on Friday.

Thirty people will be allowed to gather outdoors (up from 20), group bookings at hospitality venues will be extended from 10 to 30 people and up to 300 will be allowed at places of worship.

Staffing at gyms will also be relaxed, with a COVID safety marshal only required when more than 20 people are working out.

From December, 300 guests will be allowed at weddings but only the bridal party will be allowed to dance.

NSW has 75 people being treated for COVID and none of them are in intensive care.

Australian Associated Press