The fatalities reported on Monday also include six women and eleven men, including an unvaccinated man in his 30s.

Chief Health Officer Dr Kerry Chant said the child had "significant underlying health conditions" and died at their south-western Sydney home.

In a Facebook post, the family of three-year-old Sebastian Moroney confirmed the boy "lost his long battle" with Niemann-Pick - a rare, inherited disease.

"Ultimately he went peacefully, surrounded by the family that loved him," uncle Avram Moshe Ze'ev wrote.

The number of people hospitalised with the virus also increased by 103, to 2030.

Of those, 159 are in intensive care. Half are unvaccinated and 47 people are on ventilators.

As pressure on the health system mounts, Dr Chant is urging those at greater risk from COVID not to delay getting a diagnosis, and asked everyone to monitor for breathlessness, so health staff can intervene early.

"We don't expect young people to get breathless or dizzy and that's a sign you really need to escalate your care," she said.

There were 20,293 new infections reported from 84,333 PCR tests on Monday.

There is no way to report rapid test results in NSW yet, with the system due to come online mid-week, at which point case numbers are expected to surge again.

Premier Dominic Perrottet is continuing to face criticism over the worsening Omicron outbreak, after relaxing restrictions on masks and QR codes just as it was taking hold.

Detractors like federal Labor Leader Anthony Albanese have accused him of taking a "let it rip" approach, and street artist Scott Marsh has also taken aim at the premier in his latest work - titled Domicron Perrottet - in Redfern.

The criticism seems not to faze Mr Perrottet ,who is forging ahead with a plan to return students to school amid the nation's worst outbreak.

While just over 78 per cent of children aged 12 to 15 in NSW have been fully vaccinated, primary school-aged children - those between five and 11 - only became eligible for their first dose on Monday.

With an eight week gap recommended between jabs, very few will be fully vaccinated when classrooms open their doors.

Mr Perrottet is determined children be back in the classroom day one of term one.

Opposition Leader Chris Minns says the premier needs to determine the numbers of teachers available "or at least the best estimate for the number of teachers that could potentially be infected with COVID or close contacts" to avoid staffing shortfalls that have recently affected the health system.

He has suggested turning schools into vaccination hubs to lift the rate of vaccinated children.

The government is waiting for the first of 50 million at-home rapid test kits it has purchased to begin arriving this week and is looking to buy an additional 50 million to begin arriving in February and March.

Mr Minns says until those tests arrive the government is not meeting "the minimum obligation" to provide a way for people to know whether or not they are infected.

The "extremely exorbitant" cost of the tests currently available was also hurting essential workers and their families, Mr Minns says.

Isolation requirements for more close contacts have been scrapped, as shoppers face empty shelves at supermarkets.

Furloughed food logistics and manufacturing staff are now allowed to leave self-isolation to attend work if they have no symptoms, wear a mask, and undergo daily rapid antigen testing.

Business NSW and the Restaurants and Catering Industry Association are now calling for the government to extend the rules to the hospitality sector.

However Mr Perrottet said although the sector is struggling, the focus needed to be on "essential workers".

"It is all about the balancing of risk and having society obviously functioning well."

Australian Associated Press