"Free" web and app-based games for children are under investigation following concerns that users can run up substantial costs.
The Office of Fair Trading (OFT) are investigating whether children are being pressured to pay for content within the games such as upgraded membership and virtual currency.
The OFT has contacted companies who run the games asking for information on how they market to children.
It is also speaking to parents and consumer groups calling for information about potentially misleading or commercially aggressive practices.
More top news
At least 13 people were killed in the storm, with searches underway for many more missing.
Children are risking their lives by taking part in a dangerous new social media craze called the paracetamol challenge, police have warned.
Obese mothers-to-be put their unborn child at risk of becoming overweight even while still in the womb, a senior children's doctor warns.