Costs incurred could include accommodation and rental car hire.
"Part of the issue is that Jetstar is claiming its liability is limited when consumers could be entitled to more," Duffy added.
Duffy said Jetstar was claiming it only had to provide up to $150 reimbursement per room for accommodation and up to $30 per person for meals after a delay or cancellation within the airline's control.
"This is misleading because Jetstar is misrepresenting the limits of its liability under the Civil Aviation Act," he added.
Consumer said it had contacted Jetstar about consumer rights and flight disruptions.
"Concerningly, Jetstar referred to the potentially misleading information on its website as evidence to show it is advising passengers of their rights," Consumer NZ added.
The organisation said in contrast, Air New Zealand had met with Consumer, updated its website and produced new guidelines for passengers affected by domestic flight disruptions.
Consumer NZ said the Commerce Commission should investigate the issues as soon as possible to stop Jetstar "continuing to mislead" passengers about their rights.
Jetstar said specific information about passenger rights had been available on its website for many years.
A Jetstar spokesman said the airline frequently reviewed information provided to customers online and by text and email in the event of a disruption.
"We take our obligations under New Zealand consumer and aviation law seriously and firmly reject Consumer NZ's claim that we are misleading our customers."
Jetstar said no airline wanted to cancel or delay flights, and it did everything possible to get customers to destinations on time.
"In the event of a delay or cancellation, we provide customers with a range of assistance including rebooking them on next available flights," he added.
"And depending on the circumstances, refunds or flight credits, reimbursement for accommodation, meals and other reasonable expenses."
