Children are spending huge amount of money on supposedly free computer games sold as apps through tablets and smartphones.
Games like Angry Birds, Zombie Takeover, Playmobil Pirates, and Racing Penguin are offered as free downloads on tablets such as Apple's iPad.
However, once children are playing with them, they are hit with pop up advertisements for so-called 'In-App Purchases', IAPs, the Daily Mail reports.
These might be to purchase coins or extra powers to allow the characters being controlled by the youngsters to go further and deeper into the game.
These payments are taken automatically from the credit cards of the adult owners of the tablet or smartphone via, for example, an ITunes or Google account, it added.
According to the paper, the founder of parenting website Netmums, Siobhan Freegard, cited cases where parents have been hit with bills for hundreds of pounds as the apps are often linked to their card details through iTunes.
Often the bills aren't immediate and it takes days to find out they have been charged, Freegard added.