The travel plans of thousands of passengers will continue to be affected today by Air New Zealand's grounding of most of its regional ATR fleet after cracks were found around the cockpit window on one aircraft.

The hairline cracks were discovered during a routine overnight maintenance check in Christchurch yesterday morning.

That resulted in the entire fleet of 11 ATR aircraft operated by Air New Zealand subsidiary Mt Cook Airlines being grounded in a move that forced the cancellation of about 60 flights and disrupted travel for about 3000 passengers across New Zealand.

A further 2000 are expected to be inconvenienced today.


Air New Zealand could not give specific details last night of which flights would be affected today and has asked passengers to find out the status of their flights on the company's website or by calling the contact centre.

"Mt Cook will service, at least once, all of its usual ports except Napier, and we are putting on additional capacity," said an airline spokeswoman. Regular Air Nelson services will still operate out of Nelson.

Mt Cook general manager Sarah Williamson said two aircraft would be operating today; three others required closer examination and inspection of five others was well advanced. One aircraft was in the hangar for pre-planned maintenance.

The airline regretted the cancellations and the inconvenience they caused. "However the safety of our customers, our staff and our aircraft is paramount and non-negotiable."

Passengers affected by yesterday's cancellations had mixed views on the grounding.

At Dunedin International Airport, where three inbound and three outbound flights were cancelled, travellers faced long delays until ferried to their destinations by a one-off Airbus A320 service late yesterday.

Tracy Pearson, 47, a clothing agent from Auckland, was among frustrated passengers forced to spend the day at the airport terminal.

She had arrived to find her 10.45am flight to Christchurch had been cancelled, followed later by the cancellation of the 2.30pm flight she was rescheduled to fly on.

The cancellations left her waiting for the late-afternoon Airbus service, and meant she missed a business appointment in Christchurch.

Ms Pearson criticised the airline's decision to ground the entire fleet as "over-cautious", given each aircraft had its own maintenance checks.

"Unless there's reason for themto believe a specific plane has gotany specific problem, I don't thinkthey need to treat them all thesame."

Another returning Aucklander, Monique Oomen, said she was "a little bit frustrated" after also spending the day at the terminal, but accepted the airline's decision to ground the entire fleet.