All travel out of Auckland Airport looks likely to be disrupted for several days after a digger lifting swamp kauri on a farm at Ruakaka, south of Whangarei, sliced through the airport's sole supply of jet fuel from the Marsden Point refinery.
Airport spokesman Simon Lambourne said 23 flights have been cancelled in the past 24 hours.
NZ Refining spokesman Greg McNeill said the pipeline was likely to be shut down for several days, with two engineers flying in from Canada tomorrow.
Petrol and diesel can be trucked into Auckland by tanker, but the airport depends entirely on the pipeline and is now running out of stored supplies of aviation fuel.
Passengers on an Emirates flight to Dubai this afternoon were told this morning that the flight has been diverted via Christchurch for refuelling.
Auckland Airport's departure board shows that flights to Sydney at 1.10pm, Apia at 4.10pm, Gold Coast at 4.30pm and Melbourne at 6.35pm have been cancelled.
A passenger due to fly to Dubai from Auckland later today received a text message at 1.32am saying "due to a shortage of fuel at Auckland International Airport, your flight will operate from Auckland to Dubai via Christchurch".
"The flight will depart on schedule and will stop en route for refuelling," the text read.
"Have you ever heard of anything so bizarre as an international airport running out of fuel?", the passenger, who did not want to be named, said.
McNeill confirmed that the pipeline was cut by "external damage" but was unable to confirm that a digger was trying to lift a kauri log.
Lambourne confirmed there was a shortage in fuel on site - but it was not limited to the airport.
"I can confirm the oil companies are limiting the amount of fuel they are supplying to the airport," he said.
This is "due to an issue with fuel supply in Auckland", he said.
Lambourne said passengers scheduled to fly today should check their travel details or contact their airline for more information.
"It will impact on some flights," he said.
He could not confirm whether all flights would stop in at Christchurch or be rerouted to other centres to fuel up.
That was up to individual airlines, he said.
Refining NZ spokesman Greg McNeill said the issue began on Thursday when a leak was spotted in the pipeline that supplies aviation fuel from Marsden Point to Wiri, South Auckland, near the airport.
The 170km pipeline is constantly monitored and on Thursday a drop in pressure was noticed.
A helicopter was put up to survey the pipeline and the leak was identified on farmland at Ruakaka, about 8km from the Marsden Point refinery.
A crew is now excavating around the leak to ascertain what has happened and how to resolve the issue.
A couple who live 100 metres from the site were evacuated on Thursday and are staying in a motel.
McNeill said it was unclear how long it could take to fix the problem.
He said there were stocks of fuel around the country owned by oil companies such as Mobil, and it was up to them to decide how and where they were used.
Marsden Point was still producing fuel and the companies could still access it. At this stage, it was only the aviation fuel supply that was affected.