Air New Zealand's direct New York to Auckland flight diverted to Fiji

Air New Zealand had planned a diversion for its direct New York to Auckland service to Fiji, as the flagship service faces continuing issues with unfavourable weather.

NZ1 out of New York JFK updated its evening's route to include a stop at Nadi International airport to refuel, if needed.

A spokesperson for the airline has confirmed that this is due to unfavourable weather patterns and strong headwinds in the Pacific. The flight, originally due to depart at 9:55pm local time, was scheduled to be making a stop in Fiji. The flight has already been delayed by two hours to 11.30pm.

However, the stop in Fiji was avoided after changes to the route while airborne, a spokeswoman said.

This is the third time the new route has been flown, after launching this weekend.

The inaugural 787 flight suffered similar issues with strong headwinds and difficult weather, leading the flight to offload passenger luggage and take on additional fuel in order to make the ultra-long route.

The Airline's chief operational integrity and safety officer David Morgan said that they had planned a very brief diversion to take on fuel

"Our priority is getting customers to where they need to go and getting them there safely. It'll mean a short stop in what we call a 'gas and go'," he said.

There is currently a window of just over an hour in Nadi. The airline does not foresee the need to take on fresh crew or make time for additional rest.

"We will have NZ1 home safe and sound – just a little later than expected."

Covering almost 15000km with a scheduled flight time of 17-and-a-half hours, it is the longest ever flown by the airline.

Prevailing wind directions mean it is even longer than the Eastbound AKL to JFK route, NZ2.

Air New Zealand launched NZ1 this week from JFK to AKL, the longest route ever flown by the airline. Photo / Brett Phibbs

The southbound NZ1 service is flown with reduced seats and without cargo to mange weight.

The airline says conditions for the launch week have been worse than flight planners anticipated, with stronger headwinds than the 12 months of modelling had forecast.

"Refuelling in Nadi is our standard contingency plan for these circumstances," says Morgan.

"While these sorts of headwinds are very rare, they do happen, and we've planned for it."

On Tuesday the airline told the Herald it would be conducting a review of how to reduce the chance of similar weather-related disruptions to NZ1.

Chief operating officer for Air New Zealand Alex Marren said the decision to offload 65 was "incredibly disappointing" but made on Saturday when the flight plan was altered to go around a forecast cyclone.