A Russian state-controlled missile-maker says its own investigation into the Malaysia Airlines flight MH17 crash directly contradicts one due to be published by Dutch authorities.

The Dutch Safety Board has led a team of international investigators for the past 15 months examining the shooting down of the Boeing 777 over eastern Ukraine in which 298 people were killed last year.

Their final report will be published later today.

It is widely believed the plane was brought down by a missile.

Almaz-Antey manufactures the BUK missile, fragments of which were found at the MH17 crash site.

Both the Russian and Ukrainian militaries have BUK missile systems in their arsenal.

Yan Novikov, head of Almaz-Antey, speaking at a news conference, did not specify what was in the Dutch-led report and did not say whether he had been given an advance look.

But he said evidence showed that if the plane was hit by a BUK missile, it was fired from the village of Zaroshenske.

Russia claims Zaroshenske was under Ukrainian government control at the crash.

The Dutch-led investigation is not tasked with apportioning blame or liability for the crash - although it is possible that other conclusions could indirectly indicate blame.

Its report will focus on four distinct aspects of the crash: the cause, the extent to which the passengers on board were conscious of the crash, the issue of flying over conflict areas and, finally, the question over why Dutch victims' relatives had to wait two to four days before receiving confirmation from Dutch authorities that their loved ones were on board.

MH17 was travelling from Amsterdam to the Malaysian capital Kuala Lumpur when it crashed in Ukraine on 17 July 2014 as it flew over heavy fighting between Ukrainian forces and pro-Russian separatists.

The Ukrainian and Western governments have blamed pro-Russian separatists, claiming that they used a BUK missile.

In June, Almaz-Antey said its initial investigation suggested MH17 was brought down by a model of BUK that is no longer used in the Russian military.

Speaking on Tuesday, Mr Novikov suggested that it could have been a model even older than previously believed.

He told reporters that an experiment was conducted in July in which a missile was fired at aluminium sheets mimicking an airliner's fuselage.

It found that shrapnel from that firing indicated an older missile model, he said.

Mr Novikov claimed the experiment's results were handed to the Dutch investigators, but they were not taken into account.

From the outset, the Russian government has denied any responsibility and ahead of the report's publication Russian President Vladimir Putin's spokesman accused the investigators of ignoring Russian input.

If the Dutch investigation conclusions do point to the involvement of a Russian supplied missile, it will further sour relations between Russia and the West which are particularly low following Russian military involvement in the Syria conflict.