The Ministry of Health has reported one new possible Omicron case in Auckland.
"The person works at Auckland Airport and they are not linked to previously reported Auckland Omicron cases," the ministry said in a statement this afternoon.
"The worker's infection was detected in a routine surveillance test taken on 18 January and a positive result was returned yesterday."
Whole genome sequencing is under way to determine the variant, but the case would be treated as an Omicron case.
There are 23 new community Covid cases today and 44 at the border.
The cases in the community are located in Auckland (11), Waikato (1), Lakes (8), Hawke's Bay (2) and Nelson (1).
Earlier this afternoon, the ministry confirmed a Palmerston North Covid case reported yesterday has the Omicron variant.
The case was released from a Christchurch MIQ facility on Sunday, having returned five negative tests.
They then flew from Christchurch to Auckland on flight NZ550 that day, arriving in Auckland at 3.20pm. They then flew to Palmerston North on flight NZ5121, which departed Auckland at 4.55pm.
"The case is considered to be infectious from Monday 17 January. However, if you travelled on either of these flights, as a precautionary measure, you are asked to get a test as soon as possible," the ministry said.
There are multiple exposure events associated with the person's movements, including an early childhood centre.
They have had two doses of the Pfizer vaccine and are now isolating at home.
Officials have yet to pinpoint the source of the Palmerston North Omicron case's infection.
"Whole genome sequencing has identified similarities to border cases identified in Auckland, but no direct links," the ministry said.
"It has not identified any links to cases in the Christchurch MIQ facility, suggesting that the source of infection is offshore – either in the country they travelled from or during travel to New Zealand – rather than transmission in the Christchurch MIQ facility where they stayed."
Meanwhile there are nine new Covid cases in Nelson today - all in the same household.
The cases are believed to be in Motueka.
Public health officials are investigating a recent traveller to Auckland as the possible source of infection.
Nelson Marlborough Health has told the Herald they are still awaiting test results to confirm if the new cases have the Omicron variant.
Just one Nelson case was reported in today's Covid update from the Ministry of Health.
Changes to isolation requirements have also been made. To help address the increased infectiousness of Omicron, Covid cases must now isolate for 14 days rather than 10 days, the ministry said.
"Isolation periods for cases and close contacts remain under review and are planned to change as part of the response to an Omicron community outbreak."
Eighteen people are in hospital with Covid, including one in ICU or HDU at Middlemore Hospital.
Yesterday there were 39 new cases in the community and 46 cases of Covid-19 were detected at the border.
There were 21 people in hospital, with just one in an intensive care unit.
This morning Hauora Tairāwhiti confirmed a wastewater sample taken in the region on Monday had tested positive for Covid-19.
Health officials said there were currently no confirmed cases of the infection in Tairāwhiti.
Another routine sample was being tested that was taken on Tuesday. Results for that sample were expected today.
The positive result might indicate there was a person or people in the community who had an active Covid-19 infection, officials said.
Meanwhile, three cases of Omicron have been confirmed in Auckland - and a fourth is suspected in a household contact.
Yesterday at a press conference from Labour's retreat caucus in New Plymouth, Prime Minister Jacinda Ardern confirmed that there would not be lockdowns when Omicron got into the community.
According to latest modelling almost 2000 Omicron cases a day - 10 times the Delta peak - are expected in the Auckland region in just six weeks in the event of an outbreak.
As the country prepares for the highly transmissible variant to enter the community, restrictions eased this morning in Northland.
The region moved into the orange setting, joining the rest of the country.
"We won't be able to stop Omicron entering the community, but we can use tools to try and slow it down. We need to be on guard, and ready so that is why the country will remain at orange on an Omicron preparedness setting," Ardern said.
Hawke's Bay now has a total of nine Covid-19 cases, with three more positive cases associated with a Hastings cluster now identified.
All three new cases are linked to the Hastings cluster, taking that cluster, which began when a positive case attended two fitness classes at a local church, to eight.
The ninth case was reported yesterday and is likely to have contracted Covid-19 out of the region.
Two of the new cases will be reported in the Ministry of Health's case figures today, with the third new case to be reported in tomorrow's figures, as it missed the daily reporting cut off.
Motorists are being warned to expect hazardous driving conditions.