Dutch forensic experts recovered further human remains at the crash site of downed flight MH17 in eastern Ukraine on Wednesday, but said they could not yet start salvaging the wreckage.

"A small team has recovered body parts at the site after pieces of the wreckage were lifted with a crane," the Dutch defence ministry said in a statement.

Dutch experts, who are charged with body part recovery and also leading the probe into the fatal July 17 crash that killed all 298 on board, arrived at the site on Tuesday.

They are hoping to recover the debris from the doomed Malaysia Airlines flight, amid fears that full-scale fighting could break out again.

The human remains will now be sent to Kharkiv for a first forensic check and be repatriated to the Netherlands at a later stage, the ministry said.

The Dutch team's chief official, Pieter-Jaap Aalbersberg, said his small group had "done everything they could" to retrieve body parts and personal belongings.

"To continue, we would now need heavy equipment and far more forensic experts. At this moment it's not possible," Aalbersberg said in the statement.

He added the security situation around the crash site "remained fragile".

Kiev and the West have claimed that the Boeing 777 was shot down in the conflict-torn area by separatist fighters using a BUK surface-to-air missile supplied by Russia. Moscow denies the charges, pointing the finger back at Kiev.

So far 289 victims had been identified through body parts recovered from the site, but no wreckage has been retrieved due to safety issues.

Dutch Foreign Minister Bert Koenders warned over the weekend that the last remains of MH17's victims may never be recovered as five more coffins were flown back to the Netherlands.

The Defence Ministry said work had not started yet to recover parts of the wreckage for the air crash investigation.

Representatives from the Organisation for Security and Cooperation in Europe (OSCE), which has been negotiating with separatists on behalf of the Dutch government, "were still in talks".

"Work cannot start until agreements have been finalised," the statement said, adding "the mission is ready to commence as soon as we get the green light".