Games, aimed at children, that include "commercially aggressive" in-app purchases are to be investigated by the Office of Fair Trading.
The UK government will examine whether kids are being put under unfair pressure to pay for additional content to complete these games, which are usually free to download.
The investigation follows a number of cases in which parents only discovered a child's spending after being presented with a huge bill.
In February, five-year-old Danny Kitchen was reported to have spent £1700 on free iPad game Zombies vs Ninjas. He had binged on a string of in-app purchases, each worth £69.99.
Last month, police officer Doug Crossan was forced to report his 13-year-old son Cameron for fraud after the teenager unwittingly spent £3700 of his parents' money. Crossan did so in a bid to recoup the funds.
By targeting game makers, the new investigation hopes to prevent this from happening again.
The OFT will investigate in-app purchases that are "misleading, commercially aggressive or otherwise unfair", BBC News reported - and question whether children are being specifically targeted by them.
"We are concerned that children and their parents could be subject to unfair pressure to purchase when they are playing games they thought were free, but which can actually run up substantial costs," explained the OFT's senior director Cavendish Elithorn.
In the above cases, the respective parents had not realised that the ability to spend money on in-app purchases could be limited or switched off.
But games that put unfair amounts of pressure on users to buy content may also break laws of fair trading, Elithorn added.
Apple told Eurogamer it had "no comment" at this time.