A truck driver who killed three South Korean professional cyclists in a road accident has admitted he was watching a television mounted on his dashboard at the time, police said Thursday.

Police found the TV switched on when they and other rescuers arrived Tuesday at the scene of the accident at Euiseong, 330 kilometers southeast of Seoul.

The 66-year-old trucker surnamed Baek has been detained on suspicion of dangerous driving.

His truck rammed a van which was following the women cyclists with their coach inside and pushed it into the trio. They were killed on the spot and four other people were seriously injured.

"Although the law bans drivers from watching television while driving, there isn't any (specific) penalty when caught, so we can't do anything about it," a Euiseong police spokesman told AFP.

Offenders can however be charged with another road traffic offences if they cause an accident while watching the screen.

Digital Multimedia Broadcasting (DMB) TVs are not unusual in vehicles in tech-savvy South Korea. They are programmed to cut out when the vehicle is in motion but can be configured to stay on.

Some taxi drivers in Seoul install the televisions and glance at them while driving, apparently unhindered by police.

A total of 5,505 people were killed in 226,878 auto accidents in South Korea in 2010, the Korea Transportation Safety Authority said. (AFP)