It's been an inauspicious start for Jetstar, as glitches meant passengers flying on the budget airline's first day in New Zealand skies suffered flight delays of up to two hours.

The airline said the delays all began early in the morning with a loading machine problem in Wellington - which caused an Auckland bound flight to be delayed one hour.

The hold-ups then multiplied, a spokesman said.

"This is our first day, we've had a delay, we sincerely aplologise to everyone affected."

Jenny Prendergast, from Geraldine, said she had chosen Jetstar because of its low fares but was disappointed at the delay.

"When we checked in we weren't told anything about a huge delay, apart from everything was OK."

While Jetstar has simply taken over the New Zealand main trunk routes from its parent company Qantas, it is flying newer, bigger Airbus A320 planes, while Qantas flew Boeing 737.

Today's delays meant its inaugural Auckland-Christchurch service was 45 minutes late for a civic and media welcome.

Chief executive Bruce Buchanan, who was aboard that plane, said the delay was "unfortunate" and "unusual" for the airline which has on time performance ratings of up to 90 per cent in Australia.

The delay was caused by new staff unaccustomed to new procedures, said the airline.

One first day success for Jetstar was the public reaction to its opening day offer of 2000 free fares, which all sold out in just over one hour.

Buchanan said other cut-rate fares were selling well and more would be on the market throughout the rest of the year.

A decision on whether to expand into regional centres would be made early next year when more aircraft became available.