Crew aboard the Australian Defence Vessel Ocean Shield move the U.S. Navy's Bluefin-21 into position for deployment for another search attempt in the southern Indian OceanReuters

Australian authorities have formally ruled out the Indian Ocean search zone, where acoustic pings were picked up, as the final resting place of the missing Malaysia Airlines flight MH370.

The mystery over the jetliner's disappearance remains unsolved as the "ping zone" was thought to be the most likely region where the elusive flight could have ended up.

"The Australian Transport Safety Bureau has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgement, the area can now be discounted as the final resting place of MH370," said a statement from the Joint Agency Coordination Centre (JACC), the Australian-led agency which is leading the search operations.

The unmanned underwater vehicle Bluefin-21 has been combing the area and it has not found anything credible related to the missing plane, said the agency.

The latest finding will throw more challenges at the authorities and they will now be forced to review the satellite data reviving the hunt. The Beijing-bound flight originating from Kuala Lumpur was carrying 239 people when it vanished on 8 March.

Following weeks of multi-national search efforts, four acoustic pings were detected from the Indian Ocean and they were earlier believed to have emanated from the MH370's black box.

"Bluefin-21 completed its last mission searching the remaining areas in the vicinity of the acoustic signals detected in early April by the towed pinger locator," the JACC said.

"The data collected on yesterday's mission has been analysed. As a result, the JACC can advise that no signs of aircraft debris have been found by the autonomous underwater vehicle since it joined the search effort."

The latest statement has come a day after the US navy's civilian deputy director of ocean engineering, Michael Dean, said he believed the detected "pings" were not that of the MH370.