An Air New Zealand flight from the Covid-19 free Cook Islands has been named as a location of interest.
Flight NZ945 from Rarotonga arrived in Auckland at 5.30pm on Tuesday this week.
Passengers seated in rows 53 to 57 - indicating the infected person may not have been a crew member - were considered close contacts.
They should self-isolate, get tested immediately and again on day five after exposure, the Ministry of Health said.
"Further isolation and testing requirements will be provided by Public Health."