Panic-stricken and fumbling for a response, the crew of a South Korean ferry dithered over the evacuation of passengers in the crucial final moments before it sank, a transcript released Sunday revealed, as divers began retrieving bodies from the vessel.

Investigators arrested ferry captain Lee Joon-Seok on Saturday along with a helmsman and the ship's relatively inexperienced third officer, charging them with negligence and failing to secure the safety of hundreds of passengers -- most of them children on a high school holiday trip.

In the final nerve-wracking moments before the vessel began listing dangerously, an unidentified crew member on the 6,825-tonne Sewol repeatedly asked an official from Jindo Vessel Traffic Services (VTS) whether help was on the way.

"We are listing. Now we are about to go down," the crew member said. "It has tilted so much and we can hardly move."

In another message, the crew member revealed that safety instructions couldn't be relayed to passengers as the PA system on board was broken at that crucial moment.

Regardless, "please advise passengers to wear life jackets and wear as many layers as possible," the VTS official retorted.

"Would passengers be rescued immediately once evacuated?" the crew member said in response.

"Make them wear a life ring at least and let them float. Now!" the official insisted.

The crew have faced vehement criticism over the delay in mobilising passengers as the ship first foundered, a possibly fatal error of judgement before the vessel fully submerged with hundreds trapped on board.

Experts have suggested that many more people might have escaped if they had moved to reach evacuation points before the ship listed sharply and water started flooding in.

The dramatic transcript released by South Korean officials is bound to fuel anger among distraught relatives of the passengers, some of whom scuffled with police on Sunday over what they say has been a botched response to the disaster.

The confirmed death toll from the disaster stands at 59 so far, with 243 people still unaccounted for.

'Save my child'

Coastguard officials said 19 bodies had been removed from the ship which sank on Wednesday morning, pushing operations further along the painful transition from rescue to recovery and identification.

It was a key moment for distraught relatives, who have clung desperately to the hope that some passengers may have survived in air pockets in the upturned vessel.

Bodies were placed in tents at the harbour on Jindo island -- not far from the disaster site -- where the relatives have been camped out in a gymnasium since the ferry went down.

In a process that looks set to be repeated with tragic frequency in coming days, they were checked for IDs and other particulars, after which their relatives were informed and asked to make an official identification.

Some of the policemen standing guard at the tents were openly weeping, while the cries of the family members could be heard from inside.

Of the 476 people on board the Sewol, 350 were high school students headed for the holiday island of Jeju.

Nearly 200 family members set off Sunday on a hike from Jindo to Seoul -- 420 kilometres (260 miles) to the north -- where they planned to march on the presidential Blue House in protest over the rescue efforts.

Scuffles broke out when they were prevented from crossing the bridge to the mainland by a large police detachment, and eventually they were forced to turn back.

One of the marchers, Chung Hye-Sook, said she was appalled that the authorities had begun taking DNA samples to ease identification of the bodies before the entire ferry had been searched.

"What are those people thinking?" Chung shouted.

"We are asking them to save our children's lives. We can't even think about DNA testing. I want to save my child first," she said.

Three giant floating cranes have been at the disaster site off the southwest coast of South Korea for days, but the coastguard has promised it will not begin lifting the ferry until it is clear there is nobody left alive.

Only 174 were rescued when the ferry sank and no new survivors have been found since Wednesday.

The ferry tragedy looks set to become one of South Korea's worst peacetime disasters. A Seoul department store collapsed in 1995, killing more than 500 people, while nearly 300 people died when a ferry capsized off the west coast in 1993.