Relatives of German victims of Malaysia Airlines flight MH17 downed over Ukraine plan to sue the country and its president for manslaughter by negligence in 298 cases, the lawyer representing them said.

Professor of aviation law Elmar Giemulla, who is representing three families of German victims, said that under international law Ukraine should have closed its air space if it could not guarantee the safety of flights.

"Each state is responsible for the security of its air space," Mr Giemulla said in a statement emailed to Reuters.

"If it is not able to do so temporarily, it must close its air space. As that did not happen, Ukraine is liable for the damage."

Bild am Sonntag Sunday newspaper quoted Mr Giemulla as saying that by not closing its airspace, Ukraine had accepted that the lives of hundreds of innocent people would be "annihilated" and this was a violation of human rights.

The jetliner crashed in Ukraine in pro-Russian rebel-held territory on July 17, killing 298 people, two-thirds of them from the Netherlands. Four Germans died in the crash.

Ukraine and Western countries have accused the rebels of shooting the plane down with an advanced, Russian-made missile.

Russia has rejected accusations that it supplied the rebels with SA-11 Buk anti-aircraft missile systems.

Mr Giemulla planned to hand his case to the European Court of Human Rights in about two weeks, accusing Ukraine and its president Petro Poroshenko of manslaughter by negligence in 298 cases.

He would also push for compensation of up to one million euros ($AU1.5 million) per victim, Bild am Sonntag reported.

So far, the airline has offered relatives of each victim $5,000 in financial assistance but has said that would not be taken off final compensation or affect families' legal rights to claim.

Reuters