Prime Minister Jacinda Ardern is in isolation until Tuesday and has had a Covid-19 test today after being deemed to be a close contact of a positive Covid-19 case.

Ardern and Governor-General Dame Cindy Kiro were on flight NZ8273 from Kerikeri to Auckland on 22 January. Someone who tested positive for Covid-19 was on the flight which added to the Ministry of Health's website as a location of interest last night.

The result of whole genome sequencing for the case is expected today, but it is likely to be Omicron, a media statement from the prime minister's office said last night.

Ardern undertook a PCR test this morning. A statement from her office said she remained asymptomatic and continued to feel well. Results for the test are expected later today or tomorrow.

Ardern and Dame Cindy were in Northland undertaking advance filming at the Waitangi Treaty Grounds for the Waitangi Day broadcast.

The prime minister is asymptomatic and is feeling well and will be tested today and isolate until Tuesday, the statement said.

Ardern received her booster shot on 17 January.

The Governor-General and members of her staff who were also on the flight are following the same isolation instructions.

All other passengers who were on board NZ8273 are also deemed close contacts and need to self-isolate, get tested immediately and remain in isolation for 10 days following their exposure.

People who have been in contact with close contacts are not required to take any action.

The Ministry of Health's website yesterday listed a total of 18 domestic flights all around the country whose passengers are deemed to be close contacts after a positive Covid-19 case was identified on board.

Yesterday the Ministry of Health said 116 community cases of Covid-19 have either been confirmed as the Omicron variant or have been linked to a previously reported Omicron case.