"We thank customers for their patience as our team works to get them on their way as quickly as possible," the spokesman said.
Herald reporter Cherie Howie, who was on the flight, said the pilot and crew did not inform passengers about a problem until one-and-a-half hours into the flight, even though the passengers knew something was up.
"You do wonder what's going on when one of the pilots comes down the passenger cabin looking out all the passenger windows. Then about 15 minutes later we did a u-turn and I could see Mt Taranaki again, and realised we're going the wrong way.
"It was certainly a strange flight. You don't usually fly past Mt Taranaki twice on a one-way trip to Nelson," said Howie, adding the 50-seat aircraft was about three-quarters full.
The passengers were put on another flight to Nelson about 45 minutes after landing in Auckland.