A Defence Force plane has had to turn around in its tracks and return to Whenuapai Airport after reporting difficulties.
The Royal New Zealand Air Force C-130H Hercules has landed safely, with firefighters on standby at the airbase.
A Defence Force spokesman said the plane landed without incident after experiencing a "technical problem" with one of its four engines.
The engine was shut down as a precaution, he said, and would now be checked over.
Fire and Emergency northern fire communications shift manager Paul Radden said it was too early to say what issue, if any, the aircraft was suffering.
Crews from Kumeu and West Harbour were sent to the airport, which is used predominantly by Defence Force aircraft.
The call was made to the fire service about 1.20pm today.
Radden said the crews were sent as standby in case the landing didn't go to plan.