Najib said the government has "pretty conclusive" intelligence reports about what happened to the jet carrying 298 people but evidence must be collected so that it can be proven beyond a doubt if the case goes to court.
The plane plunged July 17 while flying from Amsterdam to Kuala Lumpur over an area of eastern Ukraine controlled by pro-Russia separatists.
Searches of the crash site were halted Aug 6 due to concerns that fighting in the immediate area was a threat.
