Zimbabwe on Monday shrugged off a ban by a major diamond trading network on gems from its controversial Marange diamond fields, saying it was sure to find buyers in Russia and Asia.

The US-based Rapaport Diamond Trading Network, or RapNet as it is known, warned in a statement on its website that it would publicly denounce and expel any of its members who dealt in Marange diamonds.

The network links thousands of diamond suppliers and buyers across the world.

RapNet founder Martin Rapaport said that although the global diamond watchdog called the Kimberley Process (KP) had authorised Zimbabwe last week to sell nearly 900 000 carats of Marange diamonds, RapNet still viewed the gems as tainted.

"RapNet members that knowingly offer Marange (the region where the alluvial diamonds are found) diamonds for sale on RapNet will be expelled from RapNet and their names will be publicly communicated," he warned.

'Not surprised'

Zimbabwe Mining Minister Obert Mpofu told the German Press Agency dpa he was "not surprised at all".

"You might be aware that America, the European Union and the United Kingdom have made every effort to make Zimbabwe fail," he said.

"In any case, these countries do not constitute the entire market of diamonds.

"We will sell our stones to countries where they are welcome. We have countries like Russia, China, India and other Asian countries where we can market our diamonds."

The Harare government auctioned off 893 000 carats of diamonds from the Marange region, where the army is accused of gross human rights violations against illegal miners and villagers since 2008.

Buyers from the US, Lebanon, India, Israel and Russia attended the auction, which the government said boosted government coffers by around $71m.

Last year, the KP ordered Zimbabwe to suspend its diamond exports while it investigated conditions in Chiadzwa. After several visits to the area, and a partial withdrawal of the army, the KP has cleared the cash-strapped government to export gems that have been mined under KP supervision.

Not in the clear

Rapaport, however, noted that the KP green light did not automatically put Zimbabwe's diamonds in the clear.

The KP was set up to clamp down on trade in "blood diamonds" - diamonds used to fund conflicts.

Zimbabwe, which denies allegations that the army killed scores of illegal diamond diggers in 2008, has said the label cannot apply to its diamonds because there is no war in the country.

However, the KP "does not have a mandate to deny its certification for diamonds involved in human rights violations and therefore there is no assurance that diamonds with KP certification are free of human rights violations," Rapaport said.

"We strongly urge members to contact their suppliers and obtain written assurances that they are not being supplied Marange diamonds," Rapaport cautioned.