Thailand is to impose a night curfew on online gaming to curb rising rates of addiction by young players, Information and Communications Technology Minister Surapong Suebwonglee said.

Game servers, both local and overseas, will be blocked from 10:00 pm to 6:00 am daily from July 15 to September 30, while Internet cafes will also have their hours curbed to those times, Surapong told reporters.

Under particular attack is Korean role-playing game Ragnarok, which was introduced to Thailand seven months ago and reportedly now has more than 600,000 registered players here.

"As a matter of fact Ragnarok is not a violent game but its problem is that child players are becoming addicted, so we have to prevent children playing for long periods of time," Surapong said.

The minister said the curfew would be evaluated after September 30.

"If the measure is proved to be effective, it will continue. If it is not effective, additional measures will be taken into consideration," he said.

Other restrictions in the pipeline, according to the Nation newspaper, include mandatory player breaks every two hours and identification cards to ensure that players do not make profits from the games.

"Some of them play online games as a job," Surapong told the daily.

Internet cafes specialising in online gaming have mushroomed in Thailand in recent years as access prices have fallen to as little as 10 to 20 baht (24 to 48 cents) per hour.

Parents and politicians have expressed concern over children as young as seven playing games for long periods of time.