UPDATED 1:59pm: An investigation is underway after an Air Force Boeing had to make an emergency landing at its Whenuapai base, in Auckland.

The plane had to circle for about an hour before landing safety around 11 o'clock.

A statement from the Defence Force says the Boeing 757 experienced technical difficulties during a training flight.

As a precaution the crew declared what's known as a 'local emergency' with police and ambulance called to the scene.

Five personnel were onboard.