Indonesia's search and rescue agency has indicated it is one step closer to finding the crashed AirAsia jet's black box recorders after the tail of the doomed plane was located on the sea bed.

"I can confirm that what we found was the tail part from the pictures", the agency's chief Fransiskus Bambang Soelistyo said.

"Now we are still desperately trying to locate the black box."

Forty bodies have now been recovered from the Java Sea after AirAsia flight QZ8501 crashed on 28 December and a further eight bodies have been identified.

East Java Police's medical and health department confirmed the deceased as Ratri Sri Andriyani, 30, Jou Christine Yuanita, 62, Soetikno Sia, 60, Indah Juliansih, 44, Nico Giovani, 17, all from Surabaya, and Ruth Puspitasari, 26, Rudy Soetjipto, 54, and Stephanie Yulianto, 14. They were from East Java.

There were 162 passengers on board the Airbus A320-200 when it crashed into the Karimata Strait.

The pilot had asked air traffic control for permission to climb to a higher altitude to avoid threatening weather. But by the time his request was granted controllers had lost contact with the plane.

It is hoped by locating the flight's recorders the cause of the plane crash will be established.