The estimation was made Thursday following the final mission of a miniature, unmanned submarine that was scanning the ocean floor off the southwest coast of Australia.
In a statement, the Joint Agency Coordination Center said the Bluefin-21 submarine found no signs of aircraft debris during its search of 850 square kilometers of ocean floor.
It said the Australian Transport Safety Board has made a professional judgment that the area "can now be discounted as the final resting place" of the Malaysia Airlines flight.
The Boeing 777 was carrying 239 people when it disappeared from radar without a distress call on March 8, about a half hour after departing Kuala Lumpur for Beijing.
The news comes a day after a U.S. Navy official cast doubt on whether the electronic signals that led searchers to deploy the robotic submarine really emanated from the missing plane.
Navy deputy director of ocean engineering Michael Dean told CNN authorities almost universally believe the so-called "pings" did not come from the plane's black box or cockpit voice recorders, as initially thought.
Dean said the signals probably came from another man-made source, such as a nearby ship or from within the electronics of the towed pinger locator that was searching for the signals.
A Navy spokesman, Chris Johnson, dismissed Dean's remarks as "speculative and premature." In an e-mail, he said the U.S. and others continue to work to "more thoroughly understand the data."
Authorities used a series of transmissions between the plane and a communications satellite to determine that the jet crashed in the remote part of the Indian Ocean.
There, a U.S. Navy pinger locator towed by an Australian ship detected a series of signals believed to come from the plane's black box. But an extensive search of the ocean floor failed to produce any trace of the jet.
Malaysian authorities, along with the British company Inmarsat, this week released the raw satellite data used to narrow the search. Many family members of those missing hope independent analysis of the data can provide more clues about the plane's location.
Satellite data is not normally used to determine a missing plane’s location, but investigators had little other choice because the plane's communications devices were either disabled or malfunctioned during the flight.
Malaysian authorities believe someone with an in-depth knowledge of airplane systems intentionally diverted the jet, but an investigation of the pilots and passengers has not yielded any solid leads.
Australian authorities have concluded the missing Malaysia Airlines flight MH370 did not crash in the area of the southern Indian Ocean where electronic signals were detected last month.