Jetstar is under investigation by the Commerce Commission over its use of "opt-out pricing" on the airline's website.
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.
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• Air NZ hit with insurance sales warning
• Air NZ faces probe over how it sells insurance with airfares
The Air New Zealand investigation resulted in the Commerce Commission issuing a formal warning, and the airline has since suspended the practice.
Commerce Commission spokesman Christian Bonnevie today confirmed to the Herald that an investigation into a similar opt-out practice by Jetstar had been underway since the beginning of the month.