Clashes frustrate MH17 investigation team

Worsening clashes between separatists and government forces in Ukraine have again frustrated investigators trying to recover bodies and possessions from the MH17 crash site.

The joint team of Australian, Dutch and Malaysian officials were delayed and had only limited access to the crash site on Monday (Ukrainian time) because of increased shelling and gunfire in nearby areas.

Human remains and personal items of victims were recovered on the previous three days at the site, but the Australian Federal Police made no mention of similar finds on the fourth day.

Australia's special envoy Angus Houston assured that all fire was directed away from the convoy to the west, even though the sounds of battle were quite close to the investigation team.

He said the situation on the ground was monitored continuously but investigators wouldn't be walking away from their mission.

"We'll stay here as long as that takes, provided the conflict situation allows it," he told ABC radio on Tuesday.

"If there are any doubts we stop, as we did today."

The Organisation for Security and Co-operation in Europe has been seeking assurances from both sides of the conflict that the investigation team will be granted safe passage to the crash site.

It's been more than two weeks since the Malaysia Airlines passenger jet was shot down over eastern Ukraine, killing all 298 people on board including 38 Australian citizens and residents.