The Russian manufacturer of the missile system blamed for shooting down flight MH17 said Friday it would unveil the "real reasons" for the disaster on the same day Dutch investigators present their final report on the tragedy.

Almaz-Antey, the maker of the BUK surface-to-air system that the West and Kiev believe downed MH17, said it would present its version of events at a press conference on Tuesday after holding an "experiment" that entailed detonating a missile next to a plane.

The company will air its claims on the same day that Dutch investigators issue their report following a 15-month probe.

All 298 people onboard were killed when the Malaysia Airlines Boeing 777 was downed over east Ukraine on July 17 last year.

Almaz-Antey said it would "present the results of a full-scale experiment, a real simulation of an encounter between a BUK-type missile and a passenger plane."

The test "will help understand the real causes of the catastrophe," it said.

Ukraine and many in the West have accused pro-Russian rebels of blowing the airliner out of the sky with a BUK missile supplied from Russia, possibly mistaking it for a Ukrainian warplane.

Moscow has vehemently denied any involvement, providing a range of conflicting theories, including an air-to-air missile putatively launched by a Ukrainian jet.

Almaz-Antey in June said the BUK-M1 type of missile has not been produced in Russia since 1999 and is in the arsenal of the Ukrainian armed forces.

Moscow in July vetoed a UN resolution to establish an international tribunal to prosecute those responsible for the downing.

Investigators in the Dutch probe have said that they found fragments at the crash site that seem to be from a Russian-made surface-to-air missile. The report findings next week are expected to provide details but will not assign blame.