It comes as the state reported a record 21 deaths on Wednesday, including seven historical fatalities.
Residents aged 16 and older can now log any positive at-home tests they have taken this year via the ServiceNSW app or website, in a process Premier Dominic Perrottet said is "seamless".
From Wednesday, uploading the result within 24 hours is mandatory.
Police enforcement will commence next week, though Mr Perrottet concedes it will be difficult.
The premier on Wednesday said the shift was not just about counting cases but understanding who has underlying conditions and may need more care.
Those who test positive will be asked for details about their medical background and sorted into high and low risk cases, with the former to receive extra contact from NSW Health.
People who test positive on RATs will have to isolate for seven days, unless they have no symptoms and no known exposure - in which case they must do another test within 24 hours.
NSW Health has repeatedly warned the official case numbers were likely inaccurate, as so far it has counted those who have returned a positive PCR test.
The daily case numbers - which reached 34,759 on Wednesday - will include PCR and RAT statistics from later in the week.
Chief Health Officer Kerry Chant apologised for the "messy" transition to the testing approach, which she said had happened far quicker than authorities wanted.
She urged anyone who did not have access to RATs - which remain scarce - to take a PCR, especially if they have underlying conditions.
Mr Perrottet said PCR testing will still play a role, particularly as NSW struggles with RAT supply.
The new policy will make PCR lines and turnarounds shorter, he said.
The 21 new deaths reported were 17 men and four women, including one person in their 30s. Eight were unvaccinated, 12 vaccinated, and one person had received one dose.
The number includes seven deaths from between September and December 2021, and included in Wednesday's count following coronial investigations.
The number of people in hospital continues to rise, with 2242 people admitted and 175 in intensive care.
Meanwhile, Mr Perrottet confirmed his government is considering a voucher system for rapid antigen tests, along the lines of the Dine & Discover program.
The state has ordered 100 million RATs and will use them to minimise disruption to schools, transport and health services.
Schools are a high priority to receive RATs once the government procures sufficient numbers, he said.
The premier reiterated his commitment to having schools open on the first day of term, rejecting a Queensland-style postponement.
"I am passionately committed to doing it. I completely disagree with the doctors' union in relation to this space," Mr Perrottet said.
"We need kids back."
Around nine-in-10 cases in NSW are the highly transmissible Omicron variant, Dr Chant said.
While nine-in-10 ICU cases were Delta at the start of December, Omicron now makes up two-thirds of ICU cases.
Proportionally, the Omicron variant has a lower hospitalisation and ICU rate than previous variants.
More than 50 per cent of ICU patients are unvaccinated.
About one-in-five NSW adults have received a booster shot.
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