Australian police are seeking a safe window in which to access the MH17 crash site in eastern Ukraine, but renewed fighting is stopping them.

The remains of all of the victims of the MH17 disaster may never be recovered, Australian police admit as fighting intensifies around the crash site in eastern Ukraine.

Eleven Australian Federal Police officers on Sunday abandoned a planned site visit as part of a 49-member team due to heavy shelling.

The team was taking advice on a second attempt to reach the site, but it appeared fighting between Ukrainian forces and pro-Russian separatists is intensifying in the region.

“We have to prepare ourselves for the possibility that not all remains will ultimately be recovered,” AFP deputy commissioner Andrew Colvin said on Monday.

It is the first time in the AFP’s history that officers have been sent in to an active war-zone.

Investigators are concerned that if fighting continues, potentially vital evidence will be lost.

The Dutch leadership of the investigation has set a three-week deadline for the repatriation of bodily remains.

Mr Colvin said Australian police would do what they could to get in and out of the site as quickly as possible, but “safety is paramount”.

Forensic experts working in the Netherlands have identified the first body as that of a Dutch citizen.

A total of 227 coffins with the remains of most of the 298 passengers who were on the Malaysia Airlines Boeing-777 have been transported to the Netherlands for identification.

Thirty-seven Australians died on the flight.

The Organisation of Security Co-operation in Europe, which is working with the Australian and Dutch police, says much of the crucial groundwork such as photographing the site has been done over the past week.

“They already have quite a bit of information to go on,” spokesman Michael Bociurkiw said.

Foreign Minister Julie Bishop is heading to Kiev to talk to the Ukrainian government about getting parliamentary approval for the mission.

However, Mr Colvin said while political pressure was needed he was satisfied about the legality of accessing the crash site and AFP officers doing their job.

Ms Bishop said she was determined to deliver on the government’s promise of “bringing all our people home”.

She had hoped for an exclusion zone around the crash site and the nearby rebel-held town of Donetsk, where the Australian contingent is based, but it was a “fluid situation”.

Dutch Prime Minister Mark Rutte on Sunday said an international military mission to secure the MH17 crash site was “unrealistic” because sending in troops could risk them becoming directly involved in the Ukrainian conflict.

There are now 170 unarmed AFP officers in Ukraine in Donetsk, Kharkiv and Kiev.

Meanwhile, the Malaysian attorney-general Tan Sri Abdul Gani Patail on Monday claimed jurisdiction over the perpetrators and began the process for bringing them to court.

Eurojust, the European Union’s judicial co-operation unit, will assist Malaysian authorities gather evidence and collate information from the countries of crash victims.