The Malaysia Airlines jet vanished in March 2014 with 227 passengers and 12 crew during a routine flight between Kuala Lumpur and Beijing.
Searches of the Indian Ocean sea bed failed to locate the plane, with scattered debris from the Boeing 777 littering the ocean, sparking the world’s biggest ever aviation mystery.
A report by Malaysian investigators into the plane’s baffling disappearance published in July claimed mechanical problems were not to blame.
It dismissed theories the pilot and first officer crashed the plane in a suicide mission.
But the report concluded the plane was manually turned around in mid-air and was not on autopilot.
Now aviation experts Mike Exner and Don Thompson are accusing Malaysian authorities of not conducting a thorough investigation.
In an interview with AirlineRatings.com, the two experts – who are part of the Independent Group examining the disappearance of MH370 – claimed the investigation “was heavily politically influenced and delayed” and identified seven areas to focus on.
They said: “The Safety Investigation Team has failed to provide any useful analysis of data from the military radar.
“It is important to establish if, when and where descents/climbs did occur and what impact that would have on fuel endurance and other implications.
“Of course, there are the somewhat incredible statements about Indonesian and Royal Thai Air Defence Surveillance radar assets not detecting the Boeing 777 in the northern Straits of Malacca.”
A complete analysis of the “most significant” debris should also be carried out, according to Mr Exner and Mr Thompson.
More information should also be released to the the public to held independent researchers try to locate the missing plane, they said.
The IG also wants a more comprehensive analysis of debris as well as all items to be collected from the Indian Ocean territories.
“This debris must be collected and analysed for additional clues,” the group said.
The IG is also demanding to know the exact identities of crew members whose voices could be heard during radio transmissions.
Last month, aviation expert Victor Iannello claimed the Malaysian report was doctored, with message logs released by the airline and included in the safety report incomplete.