The new cases were identified from 111,231 tests in the 24 hours to 8pm on Wednesday. About 31 per cent of the tests undertaken were positive.
NSW on Thursday also reported six virus-related deaths including a vaccinated and otherwise healthy ACT man in his 20s who died at Sydney's St Vincent's Hospital.
The other fatalities were four men and a woman aged between 60 and 90. Two were from Lake Macquarie in the Hunter Region and three from western Sydney.
The number of people in hospital (1609) and intensive care units (131), as well as those on ventilators (38) also rose from the day before.
Premier Dominic Perrottet warned the state may suspend elective surgeries to relieve pressure on the hospital system.
Private hospitals could be asked to help "in managing ... these increases in cases", he said.
Many of NSW's testing sites and pathology labs are under strain due to the high demand for their services.
Mr Perrottet said the testing system was at "full capacity" and it will take time to relieve the pressure as people adjust to new testing guidelines.
Under changes approved on Wednesday by national cabinet, people who test positive after a rapid antigen test don't have to get a PCR test to confirm the result.
"If you don't have symptoms, if you're not living with someone who has COVID, you don't need to be in that (PCR) queue to get tested," Mr Perrottet added on Thursday.
Employers should also stop asking workers to get PCR tests when they're asymptomatic.
"Given the current strain on the system, (PCR tests) are taking days to come back, so the (need) as we move forward for employers to be saying that to employees, is very, very low," the premier told Sydney radio 2GB.
Some of the 50 million RAT kits recently ordered by NSW will begin arriving next week.
They will be distributed in conjunction with the federal government through pharmacies and "potentially in testing centres and vaccination hubs", as well as to frontline staff in schools, Mr Perrottet said.
The federal government continues to face calls to provide RAT kits for all Australians.
Prime Minister Scott Morrison on Wednesday announced the tests would only be provided free to six million concession cardholders across Australia, with each person able to get 10 over the next three months.
Australian Medical Association NSW chair Michael Bonning said providing some free tests did not go far enough.
"We are very supportive of the idea that a PCR test doesn't need to be the standard now for people who have already had a positive rapid antigen test," he told Nine Network on Thursday.
"(But) we need more rapid antigen tests in the community so that people can be making good choices about activity, but also detecting disease early so that then they can stay away from others."
The AMA is meeting with NSW Health on Thursday to establish how infections detected under the kits will be tracked.
Unlike PCR tests, RAT results are not registered.