A South Korean passenger ferry has capsized off the south-west coast, leaving two people dead and more than 300 missing.

According to the South Korea coastguard officials, Sewol, the 146m long ferry, was carrying 477 people at the time of the incident but only 164 have been confirmed as rescued.

Among the passengers on-board were 338 students and teachers from the Danwon high school in Ansan, Seoul, who were on a field trip to Jeju Island.

In addition to passengers, the ferry was also carrying 150 vehicles.

"The South Korean coastguard called in around 100 coastguard, navy vessels and fishing boats, and 18 helicopters to carry out the rescue operation." 

The cause of the accident is not yet known, but officials believe that the ship hit rocks about 20km off the coast of Byungpoong Island, based on information provided by rescued passengers.

The ferry hit rocks with such a force that the whole ship tilted onto its side and submerged completely.

The 6,586t ferry had left the port of Incheon, near Seoul on 15 April, where it sent a distress signal on 16 April.

The South Korean coastguard called in around 100 coastguard, navy vessels and fishing boats, and 18 helicopters to carry out the rescue operation.

The Ministry of Security and Public Administration had previously incorrectly reported that 368 people were rescued and around 100 were missing, but later clarified that this was a miscalculation.