Parents are facing hefty credit-card bills after their children unknowingly spend real money while playing free online games on mobile devices such as iPhone and iPad.
Andrea Hammond was shocked to receive a $65 bill from iTunes after her two children downloaded and played Tap Pet Hotel on her iPad.
The game is free to download and encourages players to build a doggie room and entice customers.
But to lure the fictional customers, players need to buy treats, furniture and rooms - all at a real cost, which is charged to the iTunes account. A "satchel of treats" costs $65.
Ms Hammond, of Grey Lynn, said users had to enter their account password to download the application, but no warning was given of the credit-card debit during the game.
"I never knew this type of thing existed, and it seems completely unethical. It looked safe and free."
Tap Pet Hotel is one of three applications by Pocket Gems Inc. All three games include the "in-app purchase" option under which players buy items with real money.
Ms Hammond said she wasn't satisfied with the warning that came with the game.
"Even if it is on the terms and conditions when you purchase it, to have an in-app purchase that uses real money on a credit card for something completely targeted at under 10-year-olds is not appropriate."
She has deleted the application, been refunded the amount by iTunes, and has disabled the in-app purchase option on her iPad.
Herald columnist Deborah Hill Cone faced a $1500 credit-card bill after her 6-year-old daughter played the same game for two days.
"It looks like it's a free game," she said. "But there isn't anything that comes up that highlights that now you are getting charged and you must go and check with your parents ...
"I think it's deliberately making it easy for kids to run up huge bills without being aware of it."
Hill Cone has since been refunded the amount by iTunes and has disabled the in-app purchase option.
Many parents revealed similar stories after she wrote about the "dodgy" application in her Business Herald column, she said.
In California, one woman's 4-year-old son ran up a $66.88 bill by playing the top-grossing application The Smurf's Village.
The application publishers, Capcom Entertainment, reportedly added a warning after people labelled the game a "scam".
Ministry of Consumer Affairs communications adviser Alastair Stewart said the market for free games with paid content was growing.
One example was the Disney Club Penguin, an online social networking site for 6- to 9 year-olds.
The hugely popular game is free to access, but players can upgrade to options for $64.95 a year.
Mr Stewart said if parents found themselves in a similar situation to Ms Hammond's, they should complain in writing.
Retailers could be taken to the Disputes Tribunal if the complaint could not be resolved.
NetSafe executive director Martin Cocker gives some tips:
* Smartphones and iPads are essentially computers. Treat them like computers.
* Test children's applications yourself.
* Don't save your credit-card details to your iTunes account.
* Disable the "in-app purchase" option under the Settings, General, then Restrictions option on your iPad or iPhone.
* Read the terms and conditions.