Malaysia pledges justice for MH17 victims

Malaysia's leader has vowed to fight for justice for victims of the MH17 disaster, as doubts rise over efforts to bring to trial those responsible for the death of the 298 people, including 38 Australians, killed in the crash.

Friends and family of the Australian citizens and residents who lost their lives will gather in Canberra on Friday for a national memorial service on the first anniversary of the tragedy.

Prime Minister Tony Abbott will unveil a plaque bearing the names of the victims, which will be installed next to one that honours the 88 Australians killed in the 2002 Bali bombings.

Malaysian Prime Minister Najib Razak said in a statement investigators now had a clearer picture of the possible cause of the crash, and a report was due in early October.

"A year on, the battle for truth and justice is far from over," he said.

"The end goal is clear - to bring the perpetrators to justice, and ensure they pay for this unforgivable crime."

A preliminary report in 2014 found the Malaysia Airlines plane carrying 298 passengers and crew over the Ukraine on July 17, 2014, had been brought down by a large number of "high-energy objects".

This was consistent with it being shot down by a surface-to-air missile, most likely fired by Russian-backed separatists.

Australia has joined calls for an international criminal tribunal, which Foreign Minister Julie Bishop believes will maximise the chances of co-operation and an effective prosecution.

University of Western Sydney international law expert Professor Steven Freeland said calls for a tribunal were likely to fail.

"It's likely there will be some countries that are not keen to establish another expensive international court," he said.

"More significantly, there is always the distinct likelihood that Russia would exercise its power of veto over any proposed Security Council resolution to this effect, meaning that the court could not be established."

In any case, the International Criminal Court could deal with the matter, he said.