Jetstar admits it has not paid some Kiwi travellers - who are legally entitled to a compensation - after having their domestic flights delayed or cancelled.

The airline has apologised for "letting customers down" and admitted its communication and customer service for New Zealanders has been below par, particularly in recent years amid the Covid-19 pandemic.

An alert had been issued on Jetstar's website offering customers the ability to lodge historical claims if flights had been delayed or cancelled due to reasons "within the airline's control".

It comes a day after it was revealed Australia's biggest airline Qantas had agreed to pay a penalty of AUD$100 million (NZD$110m) to settle a legal case accusing it of selling thousands of tickets for flights it had already cancelled.

Under the deal with the Australian Competition and Consumer Commission, the airline was set to launch a plan worth up to AUD$20m (NZD$22m) to compensate affected passengers.

In a statement, Jetstar says its restart following the pandemic was a difficult time, for both travellers and airlines, and its communication and customer service "could have been better".

"We sincerely apologise for letting customers down during this time," a spokesperson says.

"We are encouraging anyone who feels they may not have received adequate compensation for a New Zealand flight disruption to contact us to have their case reviewed."

It was unclear what had prompted the claim proposal or how many passengers it may affect.

Under the Civil Aviation Act, passengers have rights to either compensation or a refund if certain "engineering requirements or crew limitations" have disrupted scheduled flights.

"Where your domestic flight has been delayed or cancelled for reasons within Jetstar's control, you may have rights under the Civil Aviation Act.

"Different laws apply to international travel.

"You may also have rights under consumer laws such as the Consumer Guarantees Act."

The airline was extending an offer for a secondary claim to passengers who felt a previous request for reimbursement "was not handled correctly".

Jetstar says the customers can claim for a review if their flight was disrupted prior to 7 May 2024.

-Adam Burns, RNZ