Two more cases of the Omicron variant have been detected in NSW, bringing the state's total to 15.

A number of likely cases are expected to be confirmed later on Sunday.

NSW recorded another 286 new cases of coronavirus from 66,671 tests.

A southeastern Sydney man in his 60s was the state's only death reported.

He was fully vaccinated but had underlying health conditions and died at St George Hospital.

There are now 15 confirmed Omicron cases since the first cases were reported last week, but less than half are linked to the eight countries of concern.

A student at St Peter Chanel Catholic Primary School at Regents Park who's believed to have acquired an Omicron infection at a Villawood indoor climbing gym is among the newly confirmed cases.

Anyone who attended the gym last Saturday, November 27, between 9am and 4.30pm is a close contact and must immediately get tested and isolate.

All year three and year four students and teachers at the school are close contacts and are being asked to self-isolate.

While the growing number of Omicron infections is a concern, NSW Health says none of the 15 confirmed cases have been admitted to hospital at this stage.

NSW chief health officer Kerry Chant said on Saturday she had been pleased to see a stabilisation of cases in the regions, but metropolitan Sydney is starting to record an uptick in cases.

Most of the new coronavirus cases reported on Sunday were in Sydney, with metropolitan health districts accounting for 236 of them.

On Sunday there were 148 people in hospital, up nine from the day before, with 26 in intensive care and five on ventilators.

The state's vaccination rate remained at 94.6 per cent first-dose coverage on Saturday with 92.8 per cent fully vaccinated.