HONG KONG, July 17 -- China has launched a campaign to discourage teenage Internet gaming by requiring operators to install softwares that prevent players under 18 from spending more than three hours online.

Under government rules that went into effect on July 16, Chinese Internet gaming companies must implement a screening program that requires users to enter their identification card numbers.

The program keeps the track of the online time of players identified as under 18 and reminds them at the three-hour mark with a message asking them to stop and "do suitable physical exercise."

The software monitor slashes by half the points of underage players if they keep playing beyond three hours, and wipes their points out completely if they stay on more than five hours.

The screening program is part of a government campaign to combat Internet gaming addiction, "clean up the Internet environment" and "promote civilized Internet use," according to guidelines issued by China's General Administration of Press and Publication explaining the software.

About 10 percent of China's more than 30 million Internet gamers were underaged as of the end of 2006, according to a report by the Chinese newspaper National Business Daily reprinted on the Web site of the General Administration of Press and Publication.

The government guidelines don't flat-out denounce Internet gaming, which has become a popular pastime, stating, "measured gaming is good for the brain, but gaming addiction hurts the body."

Shanghai-based gaming company The9, which runs the popular "World of Warcraft" game in China, said on its Web site it was scheduled to launch the screening software this past Saturday at midnight. The world's most popular online game has more than 3.5 million players in China.

A spokesman for another gaming company, Tencent, was quoted as saying in the South China Morning Post Tuesday that youngsters can beat the new screening program by using false identities.

"It's hard to tell online if the player is a teenager or an adult. Many of them can register for the game using someone else's ID or even a fake ID," Song Yang reportedly said.

It wasn't immediately clear if the new restrictions led to a big drop-off in player volume.

A spokesman for The9 said he wasn't immediately available for comment. Tencent didn't respond to an e-mail seeking comment.

(Agencies)