Search teams have found a voice recorder at the bottom of the Java Sea that could hold valuable information into the final moments of a doomed Lion Air flight.

It has been more than two months since flight JT610 crashed into the sea near Jakarta, Indonesia. None of the 189 people on board survived.

An Indonesian naval lieutenant confirmed on Monday that a weak signal from the cockpit recorded had been detected several days earlier, and it was finally tracked and uncovered.

It was 30 metres underwater, and buried in eight metres of mud.

It is one of two black boxes aboard the plane – the flight data recorder black box was found in early November, about a week after the crash.

The flight data recorder provided evidence that the country’s transportation safety committee said was consistent with reports the plane’s speed and altitude were erratic.

A preliminary report released in late November showed the plane’s pilots were struggling to control the aircraft from the moment it took off.

It noted the plane’s nose was forced downwards 20-plus times in its short time in the air.

It’s hoped this new discovery will reveal more details into how and why the Boeing CO 737 MAX crashed, less than an hour after taking off.

“We don’t know what damage there is, it has obvious scratches on it,” Naval Lieutenant Colonel Agung Nugroho told Reuters.

Contact with flight JT610 was lost 13 minutes after it took off on October 29 from the capital, Jakarta, heading north to the tin-mining town of Pangkal Pinang.

The crash was the world’s first of a Boeing 737 MAX jet and the deadliest of 2018.

Investigators brought in a navy ship last week for a fresh search after a 10-day effort funded by Lion Air failed to find the recorder.

Separately, Colonel Johan Wahyudi told Metro TV the recorder had been retrieved and taken aboard the ship.

A preliminary report by Indonesia’s transport safety commission, or KNKT, focused on airline maintenance and training, as well as the response of a Boeing anti-stall system and a recently replaced sensor, but did not give a cause for the crash.

-with AAP