Thirty-nine of the new cases are in the community and 10 are in MIQ. There are four new border cases of Omicron, bringing the total in New Zealand to eight.
The Ministry of Health said none of the eight cases had been in the community.
Forty-nine infected people remain in hospital.
Of the 39 new community cases, 25 are in Auckland, 11 are in the Bay of Plenty, two are in Lakes and one is in Taranaki.
Omicron, the latest variant of concern, is believed to be more infectious than the Delta strain of Covid-19 and is sweeping through the United Kingdom and other countries.
New Zealand's first case was discovered in a returnee in MIQ in Christchurch and a further three cases were detected yesterday in Rotorua. Four more were detected today.
The three cases detected yesterday arrived in Auckland from Dubai on December 11 and were transported to a Rotorua MIQ facility on a bus chartered for international arrivals.
One of the cases travelled to Dubai from London, another one from Spain and a third one from Nigeria. They all boarded the same flight in Dubai to Auckland.
A statement from the Ministry of Health yesterday said the cases were moved to the Jet Park quarantine facility in Auckland.
The trio will complete all 10 days in an MIQ facility, rather than spending the last three days in self-isolation.
The statement from the ministry said the detection of these new Omicron cases was "not surprising" given the rapid spread of the variant overseas.
