A South Korean ship, with hundreds passengers on board, is sinking off the country's southwestern coast, CNN affiliate YTN has reported.

Among the passengers, around 320 were students who were traveling with several teachers to the resort island of Jeju. There are around 20 crew members on board.

The distress signal was received from the ferry, identified as the Sewol, around 9 AM (local time).

The South Korean government has confirmed to CNN that 161 passengers have been rescued. YTN and other local media have reported that all students aboard the ship have been saved, but remains unconfirmed by the coast guard.

One parent told the network that her child was safe, and was with 11 others. All of them jumped into water and were rescued by a ship. Of the 11, one suffered a fractured leg, but the remainder were reportedly uninjured.

The ship is listing badly, leading to authorities ordering all remaining on the stricken ship to jump into the water, YTN has reported.

The water is 12.6 degrees centigrade (55 degrees Fahrenheit). Humans can survive for around two hours at this temperature.

The students were in touch with their parents by telephone. So far, no injuries and no deaths have been reported.

President Park has ordered all available vessels, along with special operations divers, to contribute to the rescue effort, semi-official news agency Yonhap has reported. (CNN)