The UK Office of Fair Trading (OFT) published its final principles for the mobile app industry to adhere to when developing apps for children
The body has given game developers and publishers until 1 April to ensure their games comply with consumer protection law.
According to the principles, consumers should be told upfront about costs associated with games or in-game advertising, with developers stating whether personal data will be shared with third parties.
They also require that in-game payments should not be taken unless authorised by the payment account holder. This is to prevent children racking up large bills while using mobile apps without the knowledge of their parents.
Developers that fail to adhere to the principles could face enforcement action, according to the watchdog.
The body also provided guidance to parents to help ensure children are not pressured into making in-game purchases, which will also reduce the risk of unauthorised payments.
The guidelines include checking the payment option settings on their device; checking whether games on devices include in-game purchases or a social element; playing games to understand what their children will be interacting with; and being aware that updates could change game content.
The OFT launched a consultation on the guidelines in September 2013, inviting responses by 21 November.
The organisation praised the work of the games industry to improve these practices since April last year, when it launched its investigation looking at whether freemium apps are pressuring or encouraging children to pay for additional content.
Apple has been targeted a number of times by consumer groups due to the purchasing policies in its App Store.
Earlier this month the company settled a dispute concerning in-app purchasing with the US Federal Trade Commission, in which it agreed to refund a minimum of $32.5 million for in-app purchases made by children without parental consent.