Rassypnoe, Ukraine: The Australian and Dutch governments have abandoned the search for victims of the Flight MH17 disaster.

In statements overnight, prime ministerial envoy Angus Houston and Dutch Prime Minister Mark Rutte conceded that the insecurity of an intensifying separatist war in and around the search site made it impossible to continue.

The Houston statement was issued at 9.30pm in Kiev [2.30am Sydney/Melbourne], at the same time as most of the 100-plus forensic and other experts who have dodged bombs to get to the site, were mounting up for a bus ride away from the area of the crash site, to the northeastern city of Kharkiv.

Feeding into the news cycle at the start of a national day of mourning for the 38 Australian citizens and residents who died when the Malaysian Airways Boeing 777 was shot from the sky, Mr Houston’s statement is replete with positives.

“The first phase of the Dutch-led humanitarian mission to the crash site of Malaysia Airlines flight MH17 has concluded,” he said, adding: “Our purpose was to recover remains from the site. We did this swiftly and thoroughly, while it was safe to do so.”

Mr Houston also said he is confident most of the remains of MH17 victims have been recovered.

"I'm greatly encouraged by the fact that we searched high priority areas on the last three days of the search and didn't find any human remains at all," he said from Kiev.

Mr Houston alluded to a lack of security that has seen the investigators pinned down for hours at a time and actually searching for as little as 30 minutes on Monday, but the Dutch leader opted for more blunt language at a press conference in The Hague.

Promising victim families that the searchers would return to the 50 sq km site, 80km east of the besieged separatist stronghold here in Donetsk, Mr Rutte said it was too dangerous for international specialists to remain in the region where the security situation is deteriorating.

Wednesday was a classic example of the security challenge faced by the experts – a scaled down party of just a few dozen took three hours to get to the site, spent three hours waiting for the villagers of Rassypnoe to hand over just a few small pieces of debris and a single silver necklace, which local Alexei Vladimirovich,27, said he had found in his potato patch; and another hour or so avoiding small arms fire in the village before bolting northwards to their base at Soledar.

"The risks are getting higher and the rewards are getting lower," a member of the Australian team with access to the leadership's thinking on strategy told Fairfax Media.

Both Mr Houston and Mr Rutte expressed gratitude to a seemingly indefatigable team of conflict monitors from the Organisation for Security and Cooperation in Europe, who negotiated endlessly with the rebels and the Ukrainian military to secure peace on the actual site and safe passage to and from the site.

Sadly, the effort was met with mixed results, with deals agreed in the early hours of the morning becoming meaningless as the investigators’ convoy approached the site.

“I would like to express my sincere gratitude to the parties that have enabled access to the area for our international team, Mr Houston said. “I thank the Ukrainian Government for its outstanding support, and I thank the Organisation for Security and Co-operation in Europe, whose officers safeguarded Australian personnel - without them, we could not have conducted our mission.”

Mr Rutte promised victims' families the search would resume at some time in the future.

Flight 17 was shot down in Eastern Ukraine on July 17, killing all 298 on board and since then an estimated 228 coffins have been airlifted to the Netherlands.

Without addressing the oft-quoted figure of 80 bodies still unaccounted for, Mr Rutte also intimated that recently received information from a Ukrainian military doctor who had supervised the recovery operation in the days immediately after the crash "has changed the recovery team's perception of an earlier effort undertaken by local authorities."

The Dutch led-international recovery team had been observed collecting small quantities of human remains on most days that they have been on the site, but they have withheld any indication of the extent to which their finds might reduce the figure.

But Mr Rutte said it appeared that "fortunately more was done after the disaster than we thought until now."

On July 31, at a meeting in Minsk, officials from Ukraine, the OSCE and Russia, and representatives of the self-proclaimed Donetsk People’s Republic agreed to cease fire within the humanitarian corridor used by OSCE monitors to access the crash site.

The ambit of the search effort was heavily qualified on Tuesday, when Australian Federal Police Commander Mark Harrison told Fairfax Media at the crash site that the search was limited to documents and the like that would help in the forensic identification of the victims.

That jarred with comments by Mr Houston on the day the first bodies were airlifted from Kharkiv, when he told reporters that ‘all the bodies, all the possessions and all the wreckage’ were to be recovered. There was no mention at that stage of this being a first phase of the search.

Australian flags are to fly at half mast on Thursday and the nation is to pause to remember the victims and Mr Abbott is to attend a memorial service at St Patrick's Cathedral in Melbourne, at which he is to be joined by Governor-General Sir Peter Cosgrove and Opposition Leader Bill Shorten. Mr Houston is to attend a similar ceremony in Kiev.

"We will give thanks for their lives and we will pray for their loved ones," Mr Abbott said. "We will pause."