SYDNEY, July 23 -- Australian Prime Minister Tony Abbott said on Wednesday the crash site of downed Malaysia Airlines flight MH17 was still not secure and feared that the bodies of some Australian victims will never come home.

Abbott told a press conference that this situation would "be completely unacceptable for bereaved families in Australia and around the world" and called for a full forensic search of the site.

The prime minister's comments came as the MH17 victims were being loaded onto military aircraft, including an Australian C-17 plane, at Kharkiv in Ukraine for transport to the Netherlands.

All 298 people onboard the Malaysia Airlines jet, including 28 Australian nationals and nine residents, were killed after the aircraft was apparently shot down over eastern Ukraine last week.

Abbott said the recovery of human remains had been "quite unprofessional."

"Based on early inspections, we do not know how many bodies we have," he said.

"It is quite possible that many bodies are still out there in the open in the European summer, subject to interference and the ravages of heat and animals. That is the predicament in which we find ourselves."

Abbott said he had been gaining support from other world leaders over the past few days in an effort to improve security at the crash site.

"There has been strong support for securing the site, because, obviously, it is at the heart of the United Nations resolution," he said.

Abbott added the resolution insists on the dignified, respectful and professional treatment and recovery of the bodies of the victims.

"I want to stress we will work with partners, we will work under the UN resolution and only under the UN resolution, but we will bring them home," he said.