The temporary shut-down of Refining New Zealand's pipeline into Auckland is impacting all airlines operating into and out of Auckland Airport and limiting the volume of jet fuel able to be uplifted.
With the Northland pipeline estimated to take another 10 days to fix, further flight delays are expected.
The pipeline also supplies petrol and diesel to Auckland, but motorists won't feel the impact over the next few days, Mobil Oil said.
The Northern Advocate newspaper is carrying a supplied photo of a kauri log lifted from a farm at Ruakaka, where the pipeline was cut.
So far, the airline cancelled 27 flights over the weekend and a further 17 domestic and global flights in the next two days.
A breakdown in the supply of jet fuel to Auckland Airport will increase the demand for refuelling aircraft at Wellington Airport.
Qantas and Jetstar said in an emailed statement that they were working to minimise impact on customers and urged people to check their flight status online.Auckland Airport is New Zealand's largest worldwide airport with passenger numbers of around 18 million a year.
"We appreciate this will be inconvenient and will require airlines to take alternative fuelling measures."
Auckland Airport Chief Executive Mr Littlewood says the airport is putting on additional staff to help support passengers and address concerns while the disruptions remain in place.
Andrew said eventually Air New Zealand rescheduled a flight for him but the airline told him there was no guarantee he would fly.
Several long-haul services to and from Asia and North America would make refuelling stops at selected Pacific or Australian airports, it said.
Prime Minister Bill English told reporters he had instructed ministers to work closely with the companies and offer Government assistance. The contaminated soil has been removed, the refinery said.
Jordana Saccomani, who is going back to Melbourne, said she hoped the leak was fixed soon.