The deaths were of a man in his 60s, a man in his 70s and a woman in her 80s, none of them fully vaccinated. The fatalities take the toll for the current outbreak to 71.
All of NSW is currently in lockdown and police have ramped up enforcement of restrictions as authorities battle to contain the spread of the Delta strain.
Lockdown settings will remain in place in regional NSW until at least August 28 and in Greater Sydney until at least September 30.
"It is a very difficult time for them and for the broader community but particularly for those families of those three people who passed away," Health Minister Brad Hazzard told reporters on Sunday.
Of the 830 cases in the 24 hours to 8pm on Saturday, the isolation status of almost 700 remains under investigation.
There was also a record of more than 206,000 tests over the 24-hour period.
It comes after NSW recorded 825 new local COVID-19 cases in the previous 24-hour period.
Premier Gladys Berejiklian said on Saturday she'd noticed a "change in attitude" from her interstate counterparts and an acceptance "Delta is here".
The premier implored people to "be real about it" and know that vaccinations were keeping them and their loved ones out of hospital.
It was revealed on Saturday six residents of a Normanhurst aged care home's dementia ward had been diagnosed with the virus after an unvaccinated staff member worked while infectious. Four of them had declined the jab.
An illegal party in the beachside suburb of Maroubra held last weekend has led at least 16 revellers to test positive, plus some of their contacts.
Meanwhile, a concerted NSW Police operation to smother a planned anti-lockdown protest on Saturday appeared to be effective, with numbers a fraction of a demonstration last month.
Some 1500 police were involved in patrolling approaches to the CBD, while train services, taxis and ride-share services were excluded.
NSW Police arrested 47 people and fined more than 260 in relation to protests across the state. They issued 137 tickets after stopping around 38,000 cars approaching the city.
Victoria has recorded 65 new locally acquired COVID-19 cases from 44,147 tests for the virus conducted on Saturday.
Health officials say 26,149 vaccine doses were also administered across the state during the 24 hours to Saturday evening.
All of Victoria is currently under orders to stay at home as infections spread in the north.
Premier Daniel Andrews says there is "every reason to believe that this is further into regional Victoria" after 21 cases were reported on Saturday from three families who have children at three local schools in Shepparton.
AAP with The Project.