Consumer NZ's CEO Jon Duffy says airlines should be required to disclose passengers' entitlements under the Civil Aviation Act.
If the reason behind any cancellation or delay is within an airline's control, the affected customers have certain rights - but airlines aren't required to disclose those rights, leaving some passengers missing out.
"We saw a particular cluster come through in the last school holidays," Duffy said.
"You had airlines gearing back up again after Covid, you're trying to get back to full capacity domestically, you had lots of bad weather around the country so you had a lot of cancellations and a lot of delays.
"And the key things that kept coming through those stories was that people didn't know why a flight had been cancelled or delayed and therefore didn't know when their rights kicked in."
To give an example, Duffy explained: "Airlines could have been telling people that it's due to Covid (that) we can't fly this plane, but actually what they were saying is all the air staff have contracted Covid and therefore they couldn't staff the plane, so actually it was an operational matter because they couldn't resource the flight.
"And so in those circumstances it's within the airline's control and you have a whole lot of rights that flow from that."
If a flight was affected by a lockdown, natural disaster or something else outside of the airline's control, that would be different and "you're kind of on your own as a consumer". An airline may offer you a credit or refund, but they're not obligated to.
But if it is within their control, such as a mechanical issue or a staffing issue, you would be entitled to a refund or compensation in the event of a cancellation if you don't choose to accept an alternative flight from the airline.
"Also, if you're put to expense - say you have to stay a night in a location because the airline can't put you on a flight until the next day - you're actually entitled to claim back your accommodation costs, your meal costs, and any transfers from the airport, that sort of stuff."
Consumer NZ are petitioning to "demand airlines tell you what your rights are if your flight is delayed or cancelled".
The petition includes an statement reading: "Air NZ has updated its website and produced a guide for passengers affected by cancellations or delays. We welcome this progress and would like to see Jetstar do the same."