Soldiers acting as pall bearers Wednesday carried coffins containing the first two bodies from AirAsia Flight QZ8501 into Surabaya airport, from where the ill-fated plane departed, as sombre relatives gave their DNA to help identify loved ones.

The bodies were taken from an air force plane to a military ambulance to be transported to a hospital for examination and identification -- but many exhausted families were left waiting for news as bad weather hampered search efforts.

Officials had hoped to recover most of the bodies but rough conditions made it difficult for helicopters to fly over the area in the Java Sea where several corpses and debris from the Airbus A320-200 were found a day earlier.

In Indonesia's second-biggest city Surabaya, where the plane had departed for Singapore early on Sunday, drained and emotional relatives of the 162 people on board gathered at a crisis centre to hand over documents and medical records.

Among them was Hadi Widjaja, 60, who was preparing a Muslim funeral for his son Andreas and daughter-in-law Enny Wahyuni.

"I am anxious to know if the rescuers have found their bodies. The president has said that they will do the best they can to find them," Widjaja told AFP.

"But if they really cannot find them, I will scatter flowers in the sea here as a way to say goodbye."

Police in Surabaya said they had taken DNA from 30 immediate family members to assist with the identification of bodies at a local hospital, to which the crisis centre is also being shifted.

Seven bodies have been recovered from the sea so far, officials said, and all of them were due to reach Surabaya by Wednesday night.

'We turned back'

Storms delayed the start of operations on Wednesday and helicopters were later forced to return to the base in Pangkalan Bun, the town with the nearest airstrip to the crash site.

"For the safety reasons, we turned back," helicopter pilot Tatang Onne Setiawan told AFP.

"Besides the evacuation of the bodies, we also planned to search for bigger parts of the plane."

Boat-based teams called off the search for bodies as night fell, but ships with sonar equipment were continuing their search for the plane's fuselage.

AirAsia boss Tony Fernandes denied reports that sonar images had located the aircraft on the seabed.

"There is no sonar, nothing, some visual identification but nothing confirmed," he told reporters.

He said however that the search team was "feeling more comfortable. They are beginning to know where it is".

During Tuesday's searches, an air force plane saw a "shadow" on the seabed believed to be the missing plane, where search efforts have since been concentrated.

Debris found from the aircraft, which crashed into the Java Sea southwest of the island of Borneo during a storm, included an exit door and several suitcases.

"There were snacks, instant porridge, and three umbrellas," commander of the Bung Tomo warship, Colonel Yayan, told a local news channel, referring to the 28 items that had been retrieved.

According to search and rescue officials AFP spoke with, none of the victims found so far was wearing a lifejacket.

The hunt is now on for the plane's black boxes, which are key to determining the cause of the crash.

"We have concerns to secure the flight recorders, believed to be with parts of the plane we haven't found," said National Search and Rescue Agency chief Bambang Soelistyo.

Britain's Air Accidents Investigation Branch has sent an investigator carrying "specialist technical equipment" that can help to locate flight recorders.

International search effort

Accompanying Singaporean experts, the investigator is travelling to the site on an Indonesian naval vessel, according to the British embassy in Jakarta.

Before take-off the pilot of QZ8501 had asked for permission to fly at a higher altitude to avoid the storm, but his request was not approved due to other planes above him on the popular route, according to AirNav, Indonesia's air traffic control.

In his last communication, the pilot said he wanted to change course to avoid the menacing storm system. Then all contact was lost, about 40 minutes after the plane had taken off.

The missing plane was operated by AirAsia Indonesia, a unit of Malaysia-based AirAsia, which had previously earned a solid safety record.

Of the 162 passengers and crew on board Flight QZ8501, 155 were Indonesian.

President Joko Widodo met the victims' families in Surabaya on Tuesday and promised "a massive search" effort, with priority given to recovering bodies of the passengers and crew.

The United States, Australia, Singapore, South Korea and Malaysia are among the countries helping in the search effort, which comes at the end of an awful year for Malaysian air travel.

After the disappearance of Flight MH370 in March, en route from from Kuala Lumpur to Beijing with 239 passengers and crew, another Malaysia Airlines flight -- MH17 -- was shot down over Ukraine in July, killing all 298 on board.