President of the World Federation of Diamond Bourses, Avi Paz said the decision to ban the Zimbabwe diamonds follows reports of violations of the Kimberly Process – a system meant to prevent trade in conflict diamonds.
The ban affects only the Marange deposits in eastern Zimbabwe, where local media have reported forced evictions of small-scale miners.
"The WFDB and its membership worldwide are committed to do all it can to prevent conflict diamonds from Zimbabwe or from any other source for that matter to be traded by our members," Paz said in a statement.
The group only allows its member bourses to trade in diamonds that are accompanied by a Kimberly Process certificate, meant to guarantee that the gems are not fuelling conflicts.
"Any bourse member who trades in rough diamonds without KP certification is liable for expulsion from his bourse, which in all practical terms means the exclusion from the entire diamond business community," Paz said.
Government officials made no immediate reaction as they are attending a weekend retreat in the resort town of Victoria Falls.
Last year, Zimbabwean authorities sealed off an eastern mining area, where the state-run Zimbabwe Mining Development Corporation is now extracting up to 60 000 carats per week, according to official figures.