MUROWA Diamond Mine increased its diamond output by 28 percent in the first half of this year, despite losing money partly due to an export ban imposed by the government.

RioZim Limited, the minority shareholder in the venture said diamond production at the Murowa had risen to 85,939 carats from 67,000 in the same period in 2009.

Global resources group, Rio Tinto controls 78 percent of Murowa, with the remainder owned by locally listed the Zimbabwe Stock Exchange (ZSE) listed mining group RioZim, which Rio Tinto formerly owned until 2004.

"The mine recorded its highest output in 18 months in May, and this trend has been sustained in the following months," RioZim said in statement.

Murowa recorded a $5 million loss compared with a loss of $6.5 million a year ago because of lower gem grades and the diamond export ban.

Zimbabwe had banned all diamond exports from the country in May until stones from the government's controversial Marange fields, where it operates two joint venture mines, were certified by industry regulators.

The export ban affected Murowa which is located in the Midlands town of Zvishavane as well as River Ranch mine, based in Beitbridge.

Certification includes ensuring there have been no human rights violations in the diamond trade.

Murowa's managing director told Reuters last week that he expected the mine to resume diamond exports soon, after the government sold its first batch of certified Marange diamonds.

The government auction of more than 900 000 carats from its stockpile raised about US$72 million with most of the gems being snapped up by Indian buyers.