TV programmes rated as having content appropriate for children aged between 13 and 18 years old, but with parental guidance required, must be broadcast after 8pm.

Programmes rated as having content appropriate for those older than 18 can only be broadcast after 10pm.

"The Cabinet has agreed to the plan because it is aware that the media has influence over learning and development," Culture Minister Khunying Khaisri Sriaroon said.

She said a survey found that 98 per cent of children spent most of their free time watching TV. On weekdays they spent an average of 3.9 hours a day in front of a TV. On weekends their TV time increased to 5.51 hours a day.

"TV is like a window to the world," Deputy Prime Minister Paiboon Wattanasiritham said. But he echoed the concerns of the social development and human security minister.

Paiboon said that TV stations had begun rating their programmes since last December, but the ratings would only be useful if programmes were broadcast at the appropriate times.

"Many parents are not home before 8pm and they are not there when their children watch TV with content that requires guidance," he said.

Paiboon expected TV stations to take a few months to fully respond to the plan.