THE HAGUE (AFP) - International forensic experts will finally reach the Ukrainian rebel-held crash site of flight MH17 on Monday, Dutch Prime Minister Mark Rutte said on Sunday.

"The OSCE (Organisation for Security and Cooperation in Europe) intends early tomorrow to take the identification mission, with the Dutch experts, to the site," Rutte told reporters in The Hague.

He said that the Dutch would be coordinating the task of identifying the 298 dead from Thursday's Malaysia Airways crash, believed to have been caused by a missile fired by pro-Russian rebels.

Fighting has continued to rage between government forces and rebels in the east since the plane came down, with 13 people wounded in the last 24 hours just 100 kilometres (60 miles) from Grabove.

Ukrainian authorities have said they cannot guarantee the safety of investigators on the ground.

Rutte's comments came as insurgents in control of the crash site said they had in hand material resembling black boxes but promised to give them to "international investigators if they arrive".

They were also holding the bodies in refrigerated carriages until "the experts arrive", said a rebel chief who explained that fighters had moved scores of bodies "out of respect for the families".

Rutte said that he would speak with Russian President Vladimir Putin later on Sunday, having spoken with German Chancellor Angela Merkel and British Prime Minister David Cameron again.

Dutch Prime Minister Frans Timmermans, meanwhile, is due to fly to the United Nations in New York to help "build a coalition" to get the bodies back, Rutte said.

Dutch King Willem-Alexander and Rutte will meet on Monday with relatives of the 193 Dutch citizens killed in the crash.

Amid growing anger in the Netherlands over lack of access to the bodies, Rutte declined to answer questions about possible Dutch or NATO military intervention to secure the crash site.