The area in the Indian Ocean became the focus of international attention on April 11 after the Prime Minister, Tony Abbott, announced he was confident signals had been detected from MH370's black box, narrowing the search to an 850-square kilometre zone.

But on Thursday Deputy Prime Minister Warren Truss went before Parliament to say the ''pings'' were the best information the government had at the time but ''the area can now be discounted''.

Mr Truss said a ''painstaking'' search of an area up to 60,000 square kilometres would now follow an oceanographic survey of the sea floor and an extensive review of all data available surrounding the plane's disappearance.

He made the announcement after Australian aviation authorities declared the plane was not in the Indian Ocean search zone where the pings were detected, and warned a revised search could take more than a year.

''The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgment, the area can now be discounted as the final resting place of MH370,'' the Joint Agency Co-ordination Centre said on Thursday.

The latest revelations are a serious setback for the search and internationally embarrassing after the Australian government's confident assertions about the search area.

Danica Weeks, whose husband Paul is one of the missing passengers, said she was shattered by the news the search area was being expanded.

''It just is another slap in the face. It's just another long road for us and look, I'm just shattered by the news. I'm absolutely shattered,'' she said from her home in Perth.

The news further shrouds in mystery the fate of the 239 passengers and crew on board MH370,

more than two months after the plane disappeared on its flight between Kuala Lumpur and Beijing on March 8.

The Australian Navy, assisted by vessels from other countries, has spent two months searching a remote area in the Indian Ocean, where four pings had been heard.

In April Mr Abbott said the Australian navy vessel Ocean Shield had received a ''series of detections'' from a towed pinger, allowing authorities to significantly narrow the search area from 46,700 square kilometres.

''We are confident that we know the position of the black box flight recorder to within some kilometres,'' Mr Abbott said. But there are now serious doubts about whether the pings were from the aircraft's black boxes.

On Thursday the US Navy's deputy director of ocean engineering, Michael Dean, told CNN that authorities now almost universally believe the pings did not come from the onboard data or cockpit voice recorders but instead came from some other man-made source unrelated to the jetliner.

''Our best theory at this point is that [the pings were] likely some sound produced by the ship … or within the electronics of the Towed Pinger Locator,'' Mr Dean said.

The chief commissioner of the ATSB, Martin Dolan, told Fairfax that there had been constant analysis and reanalysis of the recordings, but he refused to say whether they were now regarded as coming from the search equipment.

''We are confident that it is in the Indian Ocean,'' Mr Dolan said. ''We need to reanalyse the data to refine a new search area.''

He said the next phase of the search would take up to a year.

With Georgina Mitchell