The NSPCC has called for the security features of gaming phenomenon PokemonGo to be reassessed before the app is released in the UK.
The charity said it is concerned that "basic safety standards appear to have been overlooked".
PokemonGo has emerged as a global craze with players hooked to their handsets since it launched in the US, Australia and New Zealand.
In the augmented reality game, players travel around the real world to capture and train creatures known as Pokemon - the most famous of which is Pikachu.
The NSPCC said it is worried that offenders could target unsuspecting children by using the app's geolocation feature and the charity's chief executive Peter Wanless has written to developer Niantic.
He said: "I urge you to urgently reassess your app and its security and safety features.
"We all have a responsibility to ensure that children are protected and as creators of a game with substantive reach, you have a weighty responsibility to protect your young users."
The launch date for the game in the UK has not yet been confirmed.