After recording more than 2000 fresh cases in the past week, Saturday's number has set a record for case numbers in NSW.
The four deaths were a woman in her 40s, a man in his 70s, a man in his 80s and a woman in her 70s.
Of the new local cases, 121 are linked to known outbreaks and 345 are under investigation, while 87 people were in the community for all or part of the time they were infectious.
The isolation status of 303 people is also under investigation.
Premier Gladys Berejiklian told reporters on Saturday the Cumberland shire is the new front of the virus spread, with Marylands, Auburn and Granville of particular concern.
Bayside, Strathfield and Burwood will be added to the list of LGAs subject to additional restrictions from Saturday.
Additional cases have also been identified overnight in Bexley Banksia and Rockdale.
The premier told reporters on Saturday that areas of regional NSW currently subject to lockdowns, including the Hunter and Upper Hunter, would see restrictions extended for another week.
"Given what the area is experiencing the community would understand why that's the case," she said.
An additional 8000 vaccines are being sent to Walgett, where about 80 per cent of the 6500 residents are Aboriginal.
Meanwhile, authorities have ramped up compliance checks in NSW supermarkets this weekend.
SafeWork NSW said inspectors are targeting retailers and specifically supermarkets from Saturday.
"Any business found breaking the rules may be subjected to fines and could face a closure," Director of Compliance Dimitri Argeres said in a statement.
From Monday, the Australian Defence Force will send an additional 200 soldiers to NSW on top of 550 already assisting Covid-19 efforts.
The toll for the current outbreak in NSW is now at least 40.
