The Commerce Commission will investigate whether Dutch airline KLM breached the Fair Trading Act by cancelling tickets on Friday.
The commission has received about 200 complaints from angry customers who thought they had found super-cheap flights on the airline's website, only to learn the prices were a mistake.
Prices were as low as $50 one-way from Auckland to Europe. When the airline learned of the mistake, it closed down the website and emailed the affected customers, offering full refunds but telling them the tickets had been cancelled.
But customers have a difficult case to win if they want their original tickets honoured, Ministry of Consumer Affairs consumer issues adviser Joanne Kearney told the Herald.
If customers' money had been spent and lost because of the airline's mistake, there could be a case to have that money reimbursed, she said.
Accommodation bookings, rental cars and tourist activity bookings could incur cancellation fees, and such fees were not the fault of the customers, Ms Kearney said.
However, having the original tickets reinstated by claiming the loss of a bargain would be harder to achieve, she said.
Customers have contacted the Herald and explained the disappointment their children felt when told the tickets were cancelled, and of relatives overseas left upset after learning they wouldn't be getting a visit from their New Zealand kin after all.
"That's a type of loss that is really hard to measure, and much more difficult to claim," she said.
KLM issued a statement yesterday saying they had never advertised the cheap flights.
"At all times, the lowest advertised fare on the website was $2399. It was only when customers proceeded to book a flight that the incorrect fares appeared on screen."
Those fares were caused by a "technical system error", the statement said. The airline apologised for any inconvenience and disappointment caused.
The commission said customers could send information of their case to the commission's website mail address: contact@comcom.govt.nz
