An Auckland rest home kitchen worker is believed to have Omicron.
The Ministry of Health suspects the Covid-19 positive worker has been carrying the variant and is linked to the infected Nelson family.
A Counties Manukau public health team is testing residents at the rest home Summerset by the Park Flat Bush.
Management say they found out on Saturday night.
All staff are fully vaccinated, and those who worked with the infected person are isolating and being tested.
The village and care centre is now closed to visitors, and residents have been asked to stay in their rooms.
Summerset by the Park Flat Bush is listed as a location of interest on January 18, 19, 20 and 21.
Aged Care Association chief executive Simon Wallace said for other rest homes around the country, that are Covid-free, it is mostly "business as usual" at red.
"As far as visiting goes into a rest home, families can visit if they are double-vaccinated. Visits for children can be facilitated in outdoor areas."
Wallace said rest homes have been planning for Omicron for weeks.
"The only occasion where a rest home might close down to visitors or lockdown is when they have an Omicron outbreak or a Covid outbreak in their particular facility."