JINDO - Four days after South Korea's shattering ferry disaster, grieving relatives were split Sunday over whether to approve an end to the search for survivors and let cranes raise the vessel to the surface.

There are five giant floating cranes at the scene, but President Park Geun-Hye gave her personal assurance to the families of the hundreds still missing that salvage operations would only begin after all hope of finding survivors was extinguished.

Nearly 60 people have been confirmed dead, but more than 240 are still unaccounted for -- most of them children on an organised high school holiday.

A psychological turning point came when divers began retrieving bodies from inside the ferry on Sunday.

Many relatives had hoped passengers may have survived in trapped air pockets, and feared that raising the ship would have fatal consequences.

While some remain convinced their loved ones may be alive, others have begun to accept the probability there will be no survivors, especially given the bodies found by the dive teams.

"I think the time may have come to use the large cranes," said the father of one student, who gave his surname as Lee.

"It's the practical option now, to prevent bodies being swept away by the currents and lost for good, or becoming too decomposed," Lee said.

Lee's son was one of 352 students from Danwon High School who were on the ship when it capsized.

Hundreds of distraught parents have been camping out in a gymnasium on the southern island of Jindo, not far from the disaster site.

"It has been four days. We need to do something," said another father who took to the stage of the gym during a meeting with coastguard officials at the weekend.

Fear of bodies being disfigured

"If there is no hope, then we should be able to hug our children while there's still flesh on them and we can recognise their faces," he told the other relatives.

Many family members have already taken the step of providing DNA samples to ease the future identification of bodies.

But officials remain extremely wary of formally calling off the rescue part of the operation, for fear of further upsetting relatives already incensed by what they saw as the slow and inefficient response to the ferry sinking.

When some relatives spoke during the meeting with the coastguard about bringing in the cranes, others shouted them down.

"It's outrageous! What if even a single person remains alive in the ship?" Chung Hye-Sook, the mother of one missing student told AFP, her face red with anger.

"Divers must go in and bring them out," Chung said.

On Sunday morning almost 200 relatives set off on what they said was a protest march from Jindo to the presidential Blue House in Seoul -- some 420 kilometres (260 miles) to the north.

They were later turned back by police after some minor scuffles.

Jang Chul-Soon, 37, whose mother was among the missing, acknowledged the desire to recover the bodies before they became too disfigured.

"But not if lifting the ferry would deprive any survivor of their last chance of making it," he argued.

"We must not talk about the use of cranes."