Mr Hazzard said NSW needed to be “on alert”, as Omicron cases were “doubling every two to three days”.
The vaccines were not stopping transmission of Omicron, Mr Hazzard said, based on early evidence.
“But it would appear the severity of illness is not as bad as it was with previous variants of the coronavirus,” he said.
“That’s a really, really important message.”
He called on the roughly five per cent of people who have chosen not to be vaccinated to “have a rethink” because “it may save you and it may save your family”.