A plane was 25 minutes late after a distressed passenger raised security concerns and threatened to "blow up the plane" on a domestic flight.

Air New Zealand told the Herald that Flight NZ689 returned to the gate in Wellington to offload a passenger "who raised security concerns" and needed a medical assessment before further travel.

The drama happened on Flight NZ689 on Sunday, as the plane prepared to take-off for for Dunedin.

An Air New Zealand employee told Fairfax the passenger got out of his seat and started making his way up the cabin as the safety video played.


The employee claimed the man was very upset, saying he felt unwell and wanted to get off the plane.

Fairfax said crew had to restrain the man out of fear he would open one of the plane doors and activate the emergency slide.

The employee said the man told the crew he would hurt them if they didn't let him off the plane. And at one point, he threatened to "blow the plane up".

But Victoria University of Wellington senior lecturer Dr Rebecca Priestley was right beside the passenger and said the incident was not a big deal.

She said the man had a carer with him and the plane started to make its way back to the gate once he had declared he was upset.

"The plane was already well on its way back to the gate when he said 'I hate this plane it should be blown up' and no one took it seriously."

She denied that crew were forced to restrain the man; instead they put their hands on him to reassure him. They wanted the man to sit down for safety but he wouldn't, so they also touched him to keep him safe and steady, she said.

Air New Zealand said the flight was delayed by 25 minutes.