Campaign group Global Witness has pulled out of the Kimberley Process, a scheme designed to prevent "blood diamonds" from entering the mainstream market, calling the scheme outdated and a failure, almost nine years after its launch.

Blood diamonds / Photo: Corbis

In a damning statement on Monday, Global Witness said the Kimberley Process had refused to close flaws and loopholes and accused the diamond-producing governments running the scheme of showing little interest in reform.

It said customers buying diamond jewellery still could not be sure whether or not their gems had been used to finance armed violence and abuses.

"The scheme has failed three tests: it failed to deal with the trade in conflict diamonds from Côte d'Ivoire, was unwilling to take serious action in the face of blatant breaches of the rules over a number of years by Venezuela and has proved unwilling to stop diamonds fuelling corruption and violence in Zimbabwe," said Charmian Gooch, a director of Global Witness.

"It has become an accomplice to diamond laundering - whereby dirty diamonds are mixed in with clean gems."

The Kimberley Process earlier this year allowed Zimbabwe to begin exporting diamonds from its Marange region, where diamond fields were seized by security forces in 2008 and at least 200 artisanal miners were killed, according to human rights groups.

That move has been criticised by watchdogs including HRW, Global Witness and others, and several groups walked out of Kimberley Process meeting in Kinshasa in June. Exports from Marange had been suspended since 2009, and campaigners have highlighted ongoing abuses and smuggling.

The Kimberley Process, a government-led rough diamond certification scheme, was launched in 2003 and requires member states to bring in control systems.

Global Witness, which campaigns against natural resource-related conflict, corruption and associated abuse, said it had written to the chair of the Kimberley Process to announce its withdrawal as an official observer.

The concept of "blood" or "conflict" diamonds was first highlighted by organisations like Global Witness and others in relation to countries including Sierra Leone and Liberia, where years of civil war and abuses were funded with gems.