The signals were picked up intermittently but no metal was detected at the location, said Suryadi B Supriyadi, the National Search and Rescue Agency’s operational director.
Nurcahyo Utomo, a National Commission for Transportation Safety investigator, said the sounds could not be confirmed.
A day earlier, photos and video confirmed that part of the plane’s tail had been found on the seabed – the first major wreckage seen since Flight 8501 went down on December 28 with 162 passengers and crew on board.
The cockpit voice and flight data recorders are located in the rear, but Mr Supriyadi said the pings were heard about a kilometre (half mile) from the site of the tail. It was possible the signals were coming from another source.
Officials were hopeful that the black boxes remained in the plane after the impact, and plan to hoist the tail from the seabed.
They are key to helping investigators understand what caused the Airbus A320 to go down about halfway into its flight from Surabaya, Indonesia, to Singapore.
The last contact the pilots had with air traffic control indicated they were entering stormy weather. They asked to climb to avoid threatening clouds, but were denied permission because of heavy air traffic above them. Four minutes later, the plane dropped off the radar.
Four additional bodies were recovered yesterday – two still strapped in their seats on the ocean floor – bringing the total to 48. Officials hope many of the remaining corpses will be found inside the fuselage, which has not yet been located by divers. Several large objects have been spotted by sonar.
The water is relatively shallow at about 30 metres (100ft), but this is the worst time of year for a recovery operation because of monsoon rains and wind.