MH17 search suspended over safety concerns

International experts have suspended their search for body parts at the MH17 crash site because of deteriorating security in eastern Ukraine, Dutch Prime Minister Mark Rutte says.

"It doesn't make sense to continue with the repatriation in this manner," the Dutch leader told a press conference in The Hague on Wednesday.

Rutte said increasing tension between Kiev and pro-Russian separatists in the area has made it too unsafe to continue with the search for victims' remains.

"It goes without saying that Australia and Malaysia and the Organisation for Security and Cooperation are with us on this issue," Rutte said.

"We have done what we could under the current circumstances," he said.

A total 298 passengers and crew were killed when the Boeing 777 jet flying from Amsterdam to Kuala Lumpur was blown out of the sky almost three weeks ago.

The United States says insurgents shot down the plane with a surface-to-air missile likely supplied by Russia, but Moscow and the rebels blame the Ukrainian military.

Meanwhile, Dutch investigators have said a preliminary report into the cause of the crash won't be completed by its deadline.

International regulations require investigators to file an initial report with the UN's International Civil Aviation Authority within 30 days of an accident.

"We won't make it in 30 days. The preliminary safety report will take a while still," said Sara Vernooij, spokeswoman of the Dutch Safety Board (OVV), which is leading the international investigation.

"The reason for the delay is because it's a very complex situation in Ukraine right now," she told AFP.

Asked when a preliminary report could be expected, Vernooij said the team "needed more time."

"It still could take several weeks," she said.