An engine on an Air New Zealand plane malfunctioned during a flight from Auckland to Wellington.
Air New Zealand says the oil pressure had dropped in one engine, so the pilot followed procedure and shut it down.
The Boeing 737 with 101 people on board left Auckland at 9.30am on Sunday.
The Fire Service says it was expecting the aircraft would turn back to Auckland, but was told at about 10.20am that the landing would take place at Hamilton.
It sent three fire trucks to the scene and the plane landed safely, with one engine shut down, at Hamilton at about 10.30am.
Air New Zealand said engineers would inspect the plane on Sunday afternoon.
Passengers panic
Passenger Brian Childs says about half way into the flight he heard "huge bang" that sounded like the undercarriage had gone.
"The plane just rolled badly to the right then back again to the left and then started dipping."
"I thought this was it, we're gonna die."
Mr Childs says passengers were told by staff that something had gone wrong with the plane's right engine, and it had been shut down.
Another passenger Mike O'Donnell says there was panic on board when the plane began lurching.
He says one passenger needed oxygen and others were in tears.
Mr O'Donnell says the staff kept people informed and there was applause onboard when the plane landed.
