Lee Joon-seok , the captain of a South Korean ferry that sank last year killing more than 300 people has been jailed for life by an appeal court.

The sentencing is harsher than a November verdict by a district court that sentenced Lee Joon-seok to 36 years in prison for negligence and abandoning passengers in need.

Victims' relatives criticised the verdict at the time saying it was too lenient. Prosecutors had earlier demanded the death penalty for Lee.

Lee's sentence was increased because the Gwangju High Court convicted him on homicide charges, according to court spokesman Jeon Ilho. In the November ruling, Lee was acquitted of homicide.

Lee Joon-seok, the captain of the sunken South Korean ferry Sewol, arrives for verdicts at Gwangju High Court in Gwangju, South Korea, Tuesday, April 28, 2015

The appeal court sentenced 14 other navigation crew members to terms of between 18 months and 12 years in prison, Mr Jeon said. In November they had received sentences of five to 30 years in prison.

Mr Jeon said both prosecutors and the crew members have one week to appeal against the verdicts.

Most of the victims were teenagers travelling to a southern island for a school trip. A total of 295 bodies have been retrieved but nine others are missing.

Many student survivors have said they were repeatedly ordered over a loudspeaker to stay on the sinking ship and that they did not remember there any evacuation orders made by crew members before they helped each other to flee the ship.

Lee has said he issued an evacuation order.

A year after the April 2014 sinking, the South Korean government is still reeling from public criticism of its handling of the incident, the country's deadliest maritime disaster in decades.

South Korean coast guard officers try to rescue passengers from a ferry sinking in the water off the southern coast near Jindo, south of Seoul, South Korea, Wednesday, April 16, 2014. The ferry carrying 459 people, mostly high school students on an overnight trip to a tourist island, sank off South Korea's southern coast on Wednesday, leaving nearly 300 people missing despite a frantic, hours-long rescue by dozens of ships and helicopters. At least four people were confirmed dead and 55 injured. (AP Photo/Yonhap) KOREA OUT
South Korean coast guard officers try to rescue passengers from a ferry sinking in the water off the southern coast near Jindo, south of Seoul, South Korea, Wednesday, April 16, 2014. The ferry carrying 459 people, mostly high school students on an overnight trip to a tourist island, sank off South Korea's southern coast on Wednesday, leaving nearly 300 people missing despite a frantic, hours-long rescue by dozens of ships and helicopters. At least four people were confirmed dead and 55 injured

There was violence during a Seoul rally led by relatives and their supporters earlier this month, leaving dozens of people injured.

Last week, South Korea formally announced it would salvage the ship from the ocean floor off the country's south-west coast.

Relatives of the victims hope that might locate the missing, including four students, and help reveal more details about the sinking.

Some experts are sceptical about those wishes and remain opposed to spending taxpayer's money to lift the civilian vessel.

Officials say the salvage job is estimated to cost £59.7 million to £90 million and take 12 to 18 months.

The authorities blame excessive cargo, improper storage and other negligence for the sinking, and have arrested about 140 people. Critics say higher-level officials have not been accountable.