A traveller who was taken to Middlemore Hospital from a managed isolation facility at midnight on Sunday has not returned to MIQ.
In a statement, the Northern Region Health Coordination Centre (NRHCC) said while the person had twice tested negative for Covid-19 upon arrival into the country, it was important they complete their isolation.
The patient later left the Emergency Department about 2am.
The NRHCC said the person was not discharged and police were notified at 2.25am.
Police are working to locate the person.