South Korea's Sewol ferry being raised from seabed

Salvage operators in South Korea have begun to raise the sunken Sewol ferry after almost three years in an operation costing $75 million.

304 people, including 250 teenagers from the same high-school, died in one of the country's deadliest disasters on April 14, 2014 after the Sewol capsized and sunk during a routine trip.

Lee Cheol-jo, an official at the Ministry of Ocean and Fisheries, which is in charge of the operation, said on Thursday "The work needs to be done very cautiously."

Lee said the ferry would be raised 13 metres above sea level and then moved onto a semi-submersible vessel.

He said the lifting operation that began on Wednesday, will end on Friday, but it could take around 12 to 13 days to transport it to a nearby port.

Nine bodies still missing

Many relatives are also hoping to find on the ferry nine bodies which were never recovered.

"We can't help but feel stunned seeing the ship being raised," said Lee Kum-hee, whose daughter Cho Eun-hwa is one of the nine.

"My Eun-hwa has been in that dirty place. My poor Eun-hwa. It's been heart-breaking, how cold she's been there."

The Sewol was structurally unsound, overloaded and travelling too fast on a turn when it capsized and sank during a routine voyage off the southwest coast of the country.

The captain of the ferry was arrested, tried, and found guilty of murder in 2015 and jailed for life.

More than a dozen other crew members got shorter sentences, but families of victims have been calling for a more thorough investigation.