The CEO of AirAsia, Tony Fernandes has announced that the main wreckage of flight QZ8501 has not been found and there was no sonar image of the plane.

Initial reports said sonar images showed the plane was sitting upside down on the sea bed.

He also would not confirm or deny reports of bodies being discovered with life jackets, stating it was speculation at a news conference at Surabaya airport.

But Tatang Zaenudin, an official with the National Search and Rescue Agency (Basarnas), told Reuters this had been the case.

"This morning, we recovered a total of four bodies and one of them was wearing a life jacket."

Basarnas has retrieved seven bodies, some fully clothed, which could indicate passengers on board Airbus A320-200 had time to prepare before it crashed into the Karimata Strait situated northwest of Pangkalan Bun on Borneo Island. It was initially reported by the navy that 40 bodies were recovered, but that is now reported as a "miscommunication".

According to national Indonesian newspaper, Kompas, two of the bodies found on Wednesday were believed to be a boy wearing a red jacket and a woman suspected to be a flight attendant. They have been taken to hospital for examination and identification.

Ships and planes have been scouring the Java Sea for the plane. Search and rescue divers are preparing for a mission to find the remaining passengers at the crash site tomorrow afternoon, 1 January.

Authorities hope details of the cause of the crash will be determined when the flight data recorders are located.

The pilot had asked for permission to gain a higher altitude from air traffic controllers due to the severe weather on Sunday evening. But contact was lost with the aircraft by the time permission was granted.