Wellington  - Air New Zealand is threatening to ditch IBM as its main information-technology provider after a massive failure caused its computer system to collapse, delaying up to 10,000 travellers, according to an internal e-mail leaked to the media Monday.

The failure knocked out the airline's computers for five hours Sunday, forcing check-in staff to write boarding passes and luggage tags by hand and preventing potential passengers from making bookings online.

Bruce Parton, the general manager of Air New Zealand's short-haul airlines group, told Radio New Zealand that the problem was caused by a power failure followed by a delay in getting a back-up generator running.

In an internal e-mail to staff, chief executive Rob Fyfe said that in 30 years in business, he could not recall a time when a supplier had been so slow to react.

He said that he expected more of IBM and the airline was now reviewing its options for an IT supplier the company could have confidence in. (dpa)