A consumer's rights organisation has complained to the Commerce Commission alleging Jetstar is misleading passengers about their rights and breaching the Fair Trading Act.

Consumer New Zealand said Jetstar customers could be missing out on costs they are legally entitled to for things like accommodation, rental car hire, or a flight on another airline.

"When flights are delayed or cancelled for reasons within an airline's control - which might be due to overbooking, mechanical issues, staff sickness - the airline has a responsibility to refund your flight and reimburse costs incurred from the cancellation or delay," Consumer NZ chief executive Jon Duffy said.

"This could be for things like accommodation, rental car hire and other additional costs."

He said Consumer NZ continued to receive large numbers of complaints from Jetstar customers about information provided to them when flights are cancelled or delayed for reasons within the airline's control.

"Jetstar cannot simply create their own policies that override the law and shirk their responsibility to compensate, when they are legally required to.

"It is hugely concerning to us that passengers could be missing out on costs that they are legally entitled to and are having to go to great lengths to enforce their rights," Duffy said.

Consumer contacted Jetstar about passengers' rights and flight disruptions but Jon Duffy says Jetstar responded by referring to the potentially misleading information on its website as evidence to show it is advising passengers of their rights.

In contrast, he said Air New Zealand had met with Consumer NZ, updated its website and produced new guidelines for passengers affected by domestic flight disruptions.