Prime Minister Jacinda Ardern is due to receive her COVID-19 test results on Monday.
The Prime Minister began isolating on Saturday after being confirmed as a close contact of a case.
A spokesperson for Ardern said she was tested on Sunday and is asymptomatic.
"The Prime Minister has undertaken a PCR test this [Sunday] morning as per MoH requirements. She remains asymptomatic and continues to feel well," they said.
Last weekend Ardern and Governor-General Dame Cindy Kiro were in Northland pre-recording at the Waitangi Treaty Grounds for the Waitangi Day broadcast.
They were exposed during flight NZ8273 from Kerikeri to Auckland on Saturday, January 22. The flight was added to the Ministry of Health website as a location of interest on Saturday.
Whole-genome sequencing is expected to show the case has been infected with the Omicron variant.
All other passengers on board NZ8273 are also close contacts and need to self-isolate, get tested immediately and remain in isolation for 10 days following their exposure. They will also need to follow further requirements from public health officials.
They can record their exposure online or call Healthline on 0800 358 5453 so contact tracers can get in touch.
The Governor-General and members of her staff are following the same isolation instructions. Ardern's Chief Press secretary received a negative COVID test result on Monday.
Ardern's isolation comes after 103 new community COVID-19 cases were reported on Sunday.
A person in their 70s also died with the virus while in North Shore Hospital. The Ministry of Health said they "had a number of underlying health conditions".
They were admitted to hospital on January 21 and were receiving appropriate ward-level care, the Ministry said.
