Debswana, the world's biggest diamond producing company by value, said on Tuesday it would resume production on Wednesday at three of its four mines in Botswana, after suspending output due to weak demand.

A global economic slowdown has slashed demand for diamonds, leading to output cuts in Botswana, and led to a large budget deficit for the country after revenue dried up.

Debswana, a 50/50 joint venture between the government of Botswana and De Beers, which is 45 percent owned by mining group Anglo American said in February it would close its Orapa, Letlhakane and Jwaneng mines from Feb. 25 to April 14.

On Tuesday, Debswana said in a statement production at the firm's fourth and smallest mine, Damtshaa and at Orapa No. 2 plant would remain suspended for the rest of the year because demand was expected to be depressed.

The closures had cut production costs and preserved jobs, and given the company a chance to sell off some of the diamonds that had piled up in its inventories, it said.

It had also and carried out maintenance during the closure.

At the time of suspending operations, the company was carrying uneconomic quantities of inventories (diamonds) occasioned by very low sales of the 2008 fourth quarter production, Debswana said.

Ratings agencies have cut the country's foreign currency rating outlook, and forecast the economy will contract in the 2008/09 and 2009/10 financial years. (Reporting by Moabi Phia; editing by James Jukwey)