WINDHOEK - Rights abuses in Zimbabwe diamond fields are set to dominate talks opening Monday by the global system charged with preventing trade in the gems from fuelling armed conflicts.

Calls for an international ban on Zimbabwe's diamond sales are set to dominate this week's meeting of the global body set up to prevent trade in "blood diamonds", in a key test for the regulatory regime. (AFP) Zimbabwe poses a key test for the international scheme known as the Kimberley Process, named after a South African mining town, under mounting criticism for failing to effectively stem the trade in "conflict diamonds".

Civil society groups which are part of the process are demanding the suspension of Zimbabwe's international diamond trade, after a Kimberley team documented "horrific" abuses by the army against civilians in the eastern Marange diamond fields.

"At the meeting ... KP member governments must agree to suspend Zimbabwe from importing and exporting rough diamonds," said Annie Dunnebacke from Global Witness, a British group that monitors exploitation of natural resources.

Also on the agenda are concerns about smuggling from Ivory Coast, after the United Nations last week extended an arms and diamond embargo on the west African country.

A UN report found increased diamond exploitation in the north of the country, an area still under the military control of the Forces Nouvelles group of former rebels.

"Ivorian conflict diamonds continue to be exported in spite of UN sanctions and are laundered into the legitimate KP trade through neighbouring states and international trading centres -- including both member and non-member countries," the UN report said.

Concerns over the effectiveness of the Kimberley Process have mounted, and reform of the group's consensus-based decision making is also set to be discussed during the four-day meeting in the coastal Namibian town of Swakopmund.

Kimberley was dealt a hard blow to its reputation when Ian Smillie, one of the architects of the process, resigned from its governing body last May.

"I am leaving because I feel that I can no longer in good faith contribute to pretence that failure is success" he said in a farewell letter.

"I thought in 2003 that we had created something significant. In fact we did, but we have let it slip away from us," Smillie was quoted as saying by Diamond Intelligence online.

"Problems are shifted from one internal 'working group' to another... and there is no voting," he said. "Nobody takes responsibility for action or inaction, failure or success and nobody is held responsible."

Smillie now heads the Diamond Development Initiative, an organisation that helps small-scale diamond miners.

Other countries of concern are Lebanon and Guinea, which were exporting significantly more gem-quality rough diamonds than they import, Global Witness said.

The Kimberley Process covers about 99.8 percent of the world's production of rough diamonds, with 49 members representing 75 countries working within the scheme.