The company plans to produce between 28 million to 30 million carats of diamonds this year, compared with 31.3 million carats last year. "I cannot give you an exact production but we will adjust production in accordance to stakeholders' demand," Mellier told journalists in a call. "Because of the softness in the market, we are focused on waste stripping and maintenance," he added.

Global diamond demand remains strong, with the U.S., China, Japan and the Gulf countries amounting for the bulk of diamond demand growth, while European and Indian demand remains weak, he said.

He noted that trading conditions in the mid-stream section are challenging with limited capital available to finance purchases in countries such as India. Indian demand has also ebbed as a result of the rupee devaluation, which has made dollar denominated diamonds more expensive to buy.

Mellier said given the current market condition, the company will continue to focus on waste stripping and maintenance in order to make its mines more flexible and permit it to increase output in line with a commensurate rise in demand.

Mellier also said he expects Anglo American PLC's (AAL.LN) 5.1 billion dollar purchase of a 40% stake in De Beers from the Oppenheimer family to close before August. The deal, which has already received regulatory approval, would boost Anglo's stake in the diamond producer to 85%.

Mellier also said the company is in the midst of analyzing its business opportunities in the U.S., the world's largest diamond market, after the U.S. government ruled recently that De Beers could resume normal operations following restrictions imposed upon the company since 1948.

De Beers produces and markets some 40% of the world's rough diamonds by value and generated $626 million in earnings before interest, taxes, depreciation and amortization, or ebitda in the first half of the year, up 16% compared with the second half of the last year.