Consumer NZ has launched a campaign calling for the public to lobby Jetstar over its "opt out" pricing regime.
Consumer chief executive Sue Chetwin said the regime led to customers being misled into paying for extras as Jetstar's online booking process had multiple pre-ticked boxes which meant customers might end up paying for services they didn't want.
"It takes a truly canny consumer to make their way through a Jetstar booking without having additional charges appear on the fare," she said in a statement.
Air New Zealand was recently forced to remove its pre-selected travel insurance after a warning from the Commerce Commission. But Jetstar is standing its ground.
Chetwin said the company's stance was disappointing and not in the best interests of its customers.
"We're encouraging people to let Jetstar know it needs to change its practices. We've put a standard letter on our website that consumers can use to email Jetstar chief executive David Hall and ask the company to ditch the ticks."
Chetwin said the Jetstar booking process had pre-selected boxes for travel insurance, seats and baggage.
Customers had to opt out of these services or they would pay extra.
On a return flight from Wellington to Auckland, the service charges would add $42.95 to the fare. Customers may also have to pay a credit card surcharge.
Last month the Commerce Commission revealed Jetstar is under investigation by the over the practice.
Air New Zealand faced a similar investigation over the practice in January in relation to the way insurance was automatically selected for customers booking tickets on the airline's website and mobile app.
The Air New Zealand investigation resulted in the Commerce Commission issuing a formal warning, and the airline has since suspended the practice.
A Jetstar spokesman said in a statement last month that checked baggage, seat selection and travel insurance were all pre-selected during its booking process.
"Jetstar is a low cost carrier and our pre-selected options are in line with other low cost carriers worldwide."
The pre-selected items on Jetstar's website were all are clearly displayed and easy to deselect, he said.
"Pre-selection can alert travellers to services such as travel insurance or checked baggage that they may not have considered.
"If they don't want to purchase a pre-selected product they just tick a button and continue with their booking.
"We believe our pre-selection processes comply with all laws and we are explaining our position to the Commerce Commission."