Prime Minister Jacinda Ardern this morning announced a three-stage plan to combat Omicron - with further details to be revealed on Wednesday.
New Zealand will move to the red traffic light setting at midnight tonight after nine Covid cases in Motueka were confirmed to have the variant.
Omicron is now circulating in Auckland and possibly the Nelson area, if not further, Ardern said today, adding she expected the country would stay in red for "some weeks".
"As case numbers grow, both testing and isolation approaches will change in response," she said.
Given New Zealand's low number of Delta cases, we have capacity in our system to slow down the virus, Ardern said.
"The difference to previous outbreaks is we are now well vaccinated and well prepared," she said.
Stage one would include the period where we would see up to a thousand cases a day or less.
"We expect this scenario and the initial stages of the outbreak to take up to 14 days to arrive," Ardern said.
This stage would be similar to our response to Delta, taking the "stamp it out" approach, she said.
"It includes the same contact tracing, isolation and request that everyone who has symptoms be tested at a community testing station or a primary health provider," she said.
Ardern said PCR tests would continue to be used in stage 1 but rapid antigen tests (RAT) would begin to be integrated as required.
"In this stage you will need to isolate for 14 days if you are a case and 10 days if you're a contact," she said.
Stage two would be a transition stage to adjust the system to focus much more on identifying those who are at greater risk of severe illness from Omicron, which will be a smaller percentage of cases, Ardern said.
At stage three, when case numbers are in the thousands per day, changes to contact tracing and isolation requirements would be made.
"Details of this level of the outbreak will be provided in a full walk-through with the Ministry of Health on Wednesday," she said.
She said experts didn't expect the county to be at this stage until a few weeks.
"Through the course of each stage we have a test-to-work regime and will apply to our essential workforces to keep them going."
"I know that hearing those sorts of case numbers would sound deeply concerning for people to hear. Of course we will do everything that we can to slow the spread and reduce the number of cases we experience as a nation."
The decision to move to red hinged on the results of genome sequencing for several Covid cases with no clear link to the border.
The nine Covid cases in Motueka attended a wedding in Auckland on January 13, along with a funeral, an amusement park and the Sky Tower in the following days.
These events had well over 100 people.
Director-general of health Dr Ashley Bloomfield said today "we don't yet know the source of these community cases".
They flew back to Nelson on January 16, on a flight shared an Air NZ crew member who has also tested positive with Omicron. The person then worked on a further four flights, which are all now locations of interest. 150 people on those flights have been contacted and those efforts continued this morning.
Health officials are working to understand how exactly the nine Motukea cases became infected. The level of community transmission from the group is expected to be high, Bloomfield said, and it was essential to work out the extent of the spread.
Bloomfield said it was very important that the first person infected in Motukea got tested. "We are really grateful for that," he said.
There are at least 16 Omicron cases who have been outside in the community after the highly contagious variant slipped through border controls.
That includes the Motueka cases, two Auckland airport workers, an MIQ staffer, two close contacts and another person who spent two days moving about in Palmerston North while potentially infectious after being discharged from MIQ.
New locations of interest include Auckland rest home
New locations of interest linked to the Omicron outbreak - including Auckland airport's domestic terminal - have been revealed by the Ministry of Health.
Rest home Summerset by the Park in Flat Bush is also a new location of interest.
Those at the airport terminal on Sunday January 16 from 4.15-5pm are asked to self-isolate, test immediately and on day 5 after they were potentially exposed at this location of interest. Further isolation and testing requirements will be provided by public health officials.
Those linked to the rest home who were there at the following times are being asked to self-monitor for Covid-19 symptoms for 10 days after they were exposed. If symptoms develop, get a test and stay at home until you get a negative test result.
• Tuesday January 18, 9am-3pm;
• Wednesday January 19, 9am-4.30pm;
• Thursday January 20, 9am-4pm;
• Friday January 21, 9pm-4pm.
The Health ministry said a care worker at the rest home had tested positive for Covid-19.
The worker is associated with the Nelson family cluster and is fully vaccinated.
Whole-genome sequencing is being carried out but the ministry is treating this as a contact of a known Omicron case, according to its 1pm update.