Intensifying domestic competition is driving Chinese mobile game developers into overseas markets, said Google Inc, owner of the world's most used smartphone operating system.

Japan and South Korea may become "sizeable" money-spinners for developers in China in the coming years, it added.

"Tapping into South Korea and Japan makes sense for Chinese developers, because both countries have a large smartphone user base and high sales volume in the mobile gaming sector," said Ben Zhang, China head of Google Business Solutions.