Egyptian investigators have managed to access the cockpit voice recorder of the EgyptAir flight that crashed in May after finding the memory chips are intact.

In a statement today, investigators said the "test results were satisfactory as it enabled the reading of the recorders of the CVR memory unit" in France, where the plane's black boxes are being examined.

The flight from Paris to Cairo crashed into the Mediterranean, killing all 66 people on board, for reasons that remain unknown.

The pilots made no distress call and no militant group has claimed responsibility.

The plane's flight data recorder showed that there was smoke in the toilet and onboard equipment.

Egyptian investigators plan to return to Cairo with the black boxes to continue analysing their contents.