China's first regulation governing the booming market of on-line games takes effect on Sunday, which is expected to protect children from unwholesome content and Internet addiction.

The regulation, issued by the Ministry of Culture on June 22, states that on-line games targeting minors must be free of content that leads to the imitation of behavior that violates social morals and the law.

It also requires gaming companies to develop techniques that limit the gaming time of minors in order to prevent addiction. But the regulation did not specify the techniques and the permissible gaming time.

The issue drew national attention last year following a series of deaths at boot camps for Internet addicted youth.

Further, web players will now have to register using their real names before playing games online, according to the regulation.

China's on-line population reached 420 million by June 2010, according to data from the China Internet Network Information Center.

The market value of the on-line game industry in China increased by almost 40 percent to 25.8 billion yuan (US$ 3.8 billion) in 2009.

Several separate sets of regulations will also come into force on Sunday, including one that governs army service, and another that stipulates health care institutions would face punishment for withholding certain information to patients and the public.