China is enforcing more monitoring of online games after some were found to contain banned religious or political material, a state news agency reported.
Online games are popular in China's internet cafes
The announcement adds to government controls on Chinese newspapers, television and other media.
China has more than 23 million online gamers, generating revenues of more than $850m (£440m) a year.
Distributors must now obtain approval before releasing new games, reported Xinhua news agency.
Companies must also submit monthly monitoring reports, confirming developers have not added forbidden content.
The latest round of enforcement was prompted by "a rash of problems with imported online games, some of which contain sensitive religious material or refer to territorial disputes", Xinhua said.
It said some were criticised as pornographic or too violent.
Chinese officials said distributors concealed the content of the games when applying for approval, and operators sometimes upgraded games with improper content, Xinhua reported.