For the first time, Indonesian divers have been able to enter the fuselage of the AirAsia jetliner that crashed last month into the Java Sea and retrieved six bodies, an official said.

The operations chief at Indonesia's National Search and Rescue Agency, Suryadi Bambang Supriyadi, said the divers spotted some more bodies inside the fuselage.

"Today we have evacuated six bodies from inside the fuselage," Mr Supriyadi said. "Some other bodies are still there but their position among other debris made it difficult for our divers."

A total of 65 bodies have now been recovered from AirAsia Flight 8501, which crashed on December 28 with 162 people on board while flying from Surabaya, Indonesia's second largest city, to Singapore. Authorities believe many of the other bodies are still inside the fuselage.

Rescuers have been struggling with strong currents and poor visibility in an attempt to lift the fuselage of the Airbus A320 and what appears to be the plane's cockpit from the seabed at a depth of 30 metres.

Bad weather is a suspected factor in the crash. The pilots asked to climb from 32,000ft to 38,000ft to avoid threatening clouds, but were denied permission by air traffic controllers because of heavy air traffic.

Transport minister Ignasius Jonan told parliament earlier this week that radar data showed the plane was climbing at an abnormally high rate, then dropped rapidly and disappeared. No distress signal was sent.

Officials of the National Transportation Safety Committee have ruled out sabotage. Investigators are analysing data from the aircraft's cockpit voice and flight data recorders with advisers from Airbus, the plane's manufacturer.

The head of the transportation safety committee, Tatang Kurniadi, said a preliminary report on the accident is expected to be submitted to the International Civil Aviation Organisation next week.

He said a full analysis of what went wrong with the plane could take up to a year.