All supplies of aviation fuel to Auckland Airport have been cut after a digger trying to extract kauri logs cut the oil pipeline from Marsden Point near Ruakaka on Thursday.
All flights coming into Auckland have been advised to carry enough extra fuel to get out again.
Long-haul flights are being redirected to refuelling stops at other NZ or international airports.
Engineers are being flown in from Canada to help bring oil flows through the pipeline up to full capacity gradually.
Oil companies say it will take 10 to 14 days to restore normal supplies.
Road transport fuel is not affected at this stage and can be supplied by tanker, but the pipeline was the only source of aviation fuel for the airport.
The Government has offered to help oil companies struggling with an aviation fuel crisis that threatens to disrupt air travel out of Auckland for the next "10 days to two weeks".
Prime Minister Bill English told reporters on the campaign trail in Botany today that he had instructed ministers to "offer all assistance that the Government can" to restore aviation fuel supplies.
Over the last 24 hours 27 flights have been cancelled.
NZ Refining spokesman Greg McNeill said the pipeline was likely to be shut down for at least several days, with two engineers flying in from Canada tomorrow.
Mobil Oil NZ manager Andrew McNaught said the refining company had told oil companies that it would take "between 10 and 14 days" to restore the fuel supply.
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.
The temporary shut-down of Refining New Zealand's pipeline into Auckland is affecting all airlines operating into and out of Auckland Airport and limiting the volume of jet fuel able to be uplifted.
Air New Zealand chief operations integrity & standards officer Captain David Morgan said the airline was putting a range of measures in place. These will include:
• Cancelling some domestic and Tasman services to consolidate passenger loads.
• Ensuring domestic jet services uplift maximum fuel limits when operating out of Wellington or Christchurch to reduce fuel requirements ex-Auckland.
• Requiring some long-haul services to and from Asia and North America to undertake refuelling stops at selected Pacific or Australian airports.
"Unfortunately this is an industry-wide issue caused by the physical failure of an essential fuel pipeline," he said.
"We are doing all we can to minimise the impact on our operations and on our customers, however, we do ask for patience and understanding at this time. We thank our customers in advance for their co-operation."
Any necessary schedule changes will be communicated to affected customers directly.
NZ First leader Winston Peters described the pipeline break as a "catastrophy" and "disaster".
He said he expected work to be carried out "24/7" but still questioned why it would take a 10-14 days to be repaired.
"Where was the reserve in Auckland for this event? And who's doing a full-scale inquiry into how this happened in the first place."
Z Energy spokesman Jonathan Hill said they were desperately keen to know how long the "significant disruption" would last for. Z is one of the three petrol companies that supply jet fuel to airlines at Auckland Airport and which have all been affected by the leak.
Hill said the airline industry had come up with an arrangement that meant each airline was allowed 30 per cent of what they normally take. Many were making alternative arrangements such as bringing in enough fuel so they don't need to refuel in Auckland or making a fuel stop in another airport.
"Our supply has been interrupted and the supply to our airline customers has been interrupted ... We're very sorry."
A Qantas group spokesperson said Jetstar and Qantas were working to minimise the impact to their customers as much as possible. They will reach out to any impacted customers and people are encouraged to check their flight status online.
Customers currently booked to travel into or out of Auckland over the coming week are advised to keep an eye on the Travel Alerts page of the Air New Zealand website for the latest information.
Auckland Airport chief executive Adrian Littlewood said the airport is working closely with airlines and other airport stakeholders to monitor the impact of the temporary disruption on airlines and their operations.
"We will have additional staff in the terminals supporting passengers and addressing any questions or concerns they may have. We strongly recommend that any passengers travelling over the coming days plan ahead and check with their airline for the latest information."
McNaught said extra aviation fuel would be brought in to Auckland Airport by road tanker from Marsden Point, but that would not be enough to meet the demand so the main adjustment would have to come through the 70 per cent cut in fuel allocations to airlines.
"That 30 per cent is our allocation based on the next five days. Then we will continue to engage with our airline customers going forward," he said.
He said jet fuel was supplied to other airports by ship and tanker, but Auckland Airport was normally supplied solely by the pipeline because of the huge demand at Auckland.
"Those secondary airports such as Wellington and Christchurch can cope without a pipeline, but at Auckland because of the sheer magnitude we need to use a pipeline," he said.
"What we don't have is coastal tankerage in Auckland that is suitable for jet fuel. The only wharf we have is at Wynyard Wharf and that's 100 per cent diesel. To convert that to jet fuel is a big task in itself so we have decided that a better approach is to work with the airline industry through allocations."
He acknowledged that this would be "inconvenient" and would require airlines to take alternative fuelling measures.
"This will include carrying more fuel in to enable return flights without refuelling, refuelling at other airports, and stopping to fuel at other airports on the way to and from Auckland," he said.
"Industry is working to ensure there are robust fuel supplies at other airports around New Zealand to enable usual activity.
"What's important to note here is that the refinery is still running, meaning product is still being manufactured, shipped around the country and trucked to consumers. Additionally, finished fuel imports are still coming into New Zealand.
"While the pipeline also supplies petrol and diesel to Auckland, we are confident that supply of these fuels can be maintained via industry trucking from the refinery in Whangarei, and fuel terminals at Mount Maunganui.
"If any retail customers were inconvenienced, we are confident this would be minimal and short-lived.
"The industry is working closely together to ensure additional resources and measures are put in place to bridge transport fuels into Auckland to supplement the supplies already held at the Wiri fuel terminal."
McNaught said this was the first time that the refinery-to-Auckland pipeline had experienced a fault and industry was working well, together with its stakeholders, customers and government.
Energy and Resources Minister Judith Collins said she had spoken to Refining NZ and the heads of fuel companies affected by the disruption to the Marsden Point pipeline to Auckland and offered government support if it is required.
"I have spoken to Sjoerd Post, chief executive of Refining NZ, which owns the pipeline, as well as Mobil, BP and Z Energy, which all use the pipeline to supply fuel to Auckland," she said.
"Refining NZ is doing all it can to repair the pipeline and industry is working to minimise any inconvenience to customers and the public.
"Refining NZ has all the expert technical assistance resources it needs, including international expertise. I have also offered them, and the companies supplying fuel, government assistance, if we are needed.
"There are fuel stocks on hand in Auckland and additional stocks of petrol and diesel are being trucked in directly from the refinery, and from the terminal in Mt Maunganui. The fuel companies are confident that supply of these fuels will be maintained and it is unlikely that motorists will be inconvenienced.
"The pipeline is the only source of jet fuel for Auckland Airport, so precautions have been taken to restrict the amount of fuel being used. Airlines have options to manage their operations and will be looking to minimise any inconvenience for travellers. They will keep their customers informed of any changes to flight schedules, as required."
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 1.15pm, 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.
Auckland International Airport spokesman Simon 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.
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.
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.