Prime Minister John Key is adding his voice to international calls to allow investigators free access to the crash site of Malaysian Airlines flight MH17, which was shot down over Ukraine.
New Zealand-born Australian resident Mary Menke and her husband, Gerry Menke, as well as British-born New Zealand resident Rob Ayley, were among the 298 passengers and crew who died in the disaster.
There are reports of looting at the site, amid outrage over the handling of bodies and fears the crash scene is being compromised by Ukrainian rebels.
Mr Key called on Russian President Vladimir Putin to tell the Ukrainian rebels to allow full access.
"I think the self-proclaimed deputy prime minister ... is saying that the rebels will give access when Kiev agrees to a ceasefire," Mr Key said.
"Well these are innocent families who are not getting access to justice and information because of the dispute within the Ukraine and between Russia and the Ukraine."
Mr Key said the crash scene was becoming more contaminated as the days passed, raising fears this would compromise a full investigation.
"Like me, you've probably seen some of the media reporting where you've got journalists walking around the cockpit and other parts of the sites completely unprotected," he said.
"I think only 198 of the bodies have been removed. How can you have a proper and thorough investigation when you've got a crime scene essentially that has got free access to rebels and anybody else?"
A New Zealand diplomatic envoy is in Kiev to represent New Zealand's interests.