A plane-load of passengers was stuck on the tarmac for four hours after their aircraft was diverted from Wellington to Ōhākea Airbase.
Qantas flight QF171 from Melbourne had to travel more than 100 kilometres north of Wellington, landing around 3pm.
Passengers posted to social media said they were unable to get off the plane until customs officials arrive from Wellington, and that the plane was getting incredibly hot.
One update said the flight attendants would not open the doors of the plane.
"Sitting on the tarmac in the sun, getting extremely hot in the plane. Many passengers visibly distressed," one man wrote.
Passengers reported the flight was diverted because one of the plane's flaps was stuck and the runway at Wellington was too short to land.
Qantas has told Newshub the plane has a mechanical issue and the passengers will be bussed to Wellington.
"Usually under these circumstances, the aircraft would divert to Palmerston North, however, this was not possible due to local weather conditions," they told Newshub.
Passengers were trapped on the plane as Ōhākea Airbase does not have any customs facilities.
"We needed to divert staff from the Napier office to attend, so obviously there's a timelapse before they can get there physically," said Terry Brown, group manager board of operations with New Zealand Customs.
"We did look to pre-clear the passenger process, we have pretty advanced information systems around the passengers that are on board the aircraft so were able to do that," he told Newshub.
He says he is sorry passengers were inconvenienced but the event could not have been predicted.
All passengers completed processing shortly after 8pm following MPI's arrival and are awaiting transportation by bus to Wellington.