The operator of a ferry that sank off South Korea's south coast earlier this week, leaving hundreds dead or missing, has been involved in many other accidents at sea, records showed Saturday.

Chonghaejin Marine, the owner of the ill-fated ferry Sewol, has been in marine accidents involving engine trouble and collisions every two to three years in the recent past, the records showed.

Three weeks before Wednesday's sinking of the 6,825-ton Sewol, one of Chonghaejin's passenger ships collided with a fishing boat in thick fog in the Yellow Sea. None of the 141 passengers aboard the liner were injured.

In October 2009, the same passenger ship arrived at its destination three hours later than scheduled due to engine trouble.

Passengers at the time lodged protests against the operator for informing them of the trouble only 40 minutes after the boat had stopped.

In February last year, a 6,322-ton passenger ship belonging to Chonghaejin arrived at the western port city of Incheon six hours behind schedule due to a defect in its generator.

Some of the more than 250 passengers aboard the ship demanded a refund, but the operator refused, prompting strong protests from the passengers.

In April 2011, the same boat stopped shortly after leaving Incheon due to engine trouble. After making some repairs at sea, the boat returned to the port some five hours later.

The Sewol's sinking is feared to be one of the nation's worst disasters. As if 5:30 p.m., 30 passengers were confirmed dead and more than 270 others unaccounted for. (Yonhap)