Stepping up a public morality campaign aimed at Chinese youths, the government will require official approval of all on-line and mobile game products before they are sold, state media reported Tuesday.

More than 80 per cent of the nearly 140 on-line games available in China are imported. Some have content deemed violent, sexually explicit or harmful to national security, the official Xinhua News Agency said in a report on its website.

Games already on sale must be submitted to the Ministry of Culture for approval by Sept. 1 or they will be considered unauthorized and those caught distributing them punished, Xinhuanet reported.

The report did not specify penalties.

Games that pass the checks will be given approval codes, and it will be illegal to amend their titles or content, the report said.