Initial results from a criminal inquiry into the downing of a Malaysia Airlines flight over war-torn eastern Ukraine nearly two years ago will be available within months, Dutch prosecutors have said.

The results are expected to shed light on the exact type of missile used to shoot down Malaysia Airlines flight MH17 on July 17, 2014, killing all 298 passengers and crew on board, and exactly where it was fired from.

"After this summer, the Joint Investigation Team (JIT) will present the first results of the criminal investigation into the crash of flight MH17," the public prosecutor said in a statement released late Friday.

"It concerns the weapon which was used to shoot down the aircraft and the exact launch site of the weapon," it said, noting that the inquiry was at "a very advanced stage".

However, investigators on the Dutch-led team, which includes experts from Australia, Malaysia, Belgium and Ukraine, were still awaiting information from Moscow about BUK missile installations, it said, noting that they were expecting an answer "within two months".

In October, an international inquiry concluded that the Boeing 777, which was en route from Amsterdam to Kuala Lumpur, was shot down by a Russian-made BUK surface-to-air missile fired from a zone held by pro-Russian separatists, but stopped short of saying who was responsible.

Results of the latest investigation will not be published in a report, however, but will be included in a criminal file "which is intended for the hearing of the case in a court or a tribunal," the prosecutor said, indicating this was normal procedure in criminal cases.

Earlier this week, families of six Malaysian crew members filed suit against the airline for negligence and breach of contract, their lawyer said, and the carrier could also face similar action from more MH17 next-of-kin over loss of earnings as well as compensation for the "psychological" trauma of losing loved ones.

Last month, relatives of victims from Australia, New Zealand and Malaysia launched legal action against Russia and its President Vladimir Putin in the European Court of Human Rights, The Sydney Morning Herald reported.

Documents filed by their lawyers allege that Moscow has worked to keep its involvement in the plane disaster hidden.