The United Nations Environment program will help Papua New Guinea's island of Bougainville manage on-going environmental issues associated with the Rio Tinto-owned Panguna copper mine.
The mine, which was one of the world's largest, was closed in 1989 after it became the spark which lit the civil war on the island.
There was no mine closure process when Bougainville Copper, the Rio Tinto subsidiary which owns the mine, was driven out of Bougainville.
Pollution from mine tailings has since been flowing into the environment and Dr Gavin Mudd, Senior Lecturer in Environmental Engineering at Monash University says it's a continuing problem.
"There's a lot of acid mine drainage that is leaving the site, there is also tailings going down the river. And the acid mine drainage of course has extremely high levels of metals," Dr Mudd told .
Heavy metals can accumulate in fish and vegetation and affect human health.
Inside the mine site itself, many buildings contain asbestos and some abandoned measuring instruments contain radio active material.
The United Nation's Environment Program's Geneva-based disaster risk reduction branch has agreed to help Bougainville to draw up terms of reference for the clean-up.
It will also assist with environmental studies that will help Bougainvilleans decide if they want to re-open the mine.
An international legal expert, Associate Professor Don Anton from the Australian National University, says the involvement of the United Nations Environment Program is a significant development and has a strong track record of similar problems.
"It is a very significant development in the sense that we have an independent, a proven independent third party coming in to look at a very contentious situation," Mr Anton said.
"It has been involved in other rehabilitation programs, like the Mau forest eco-system in Kenya, it has experience in remediation after hostilities, after Iraq and depleted uranium in Bosnia, so it has experience and a well respected track record in dealing with environmental problems."
Experts predict remediation of the old mine site will be a large-scale, and very expensive, exercise.
"I'd imagine you would be looking at hundreds of millions of dollars, if not billions. It is really hard to know exactly," Dr Mudd said.
"It depends on the logistics involved and there is a whole bunch of complex factors involved in that so the simple message is it is not going to be cheap. Whichever level of remediation is done at Bougainville, it is certainly going to be a very costly exercise," Dr Mudd said.
Bougainville Copper Limited is legally responsible for the clean-up.
Public opinion on Bougainville has been shifting in favour of re-opening the mine, but many people who lived through the civil war remain wary.
Associate Professor Don Anton says whichever decision is made environmental standards must be met.
"It is clear we should have a rigorous environmental impact assessment with full public participation, full disclosure, full opportunity to comment," he said.
"We should have, in terms of approvals, conditions imposed upon the operation of these mines if they were to go forward again, including the requirement for insurance, remediation bonds and other security put up to account for problems that may eventuate down the track."
The Bougainville government is yet to set up environment department department or pass legislation regarding the remediation.
Dr Anton expects the government will face challenges due to a lack of personnel and expertise.
He suggests that if the mine does reopen, strict conditions should be imposed that require financial payments that would allow the Bougainvillean government create an independent environment department whose job would be to inspect and monitor the mine.