The Central Bank of Nigeria said in April it would no longer provide foreign currency for importers of sugar and wheat as the country tries to conserve national dollar reserves and encourage local production.

In a circular dated July 16, the central bank's trade and exchange department said Dangote, which is owned by Africa's richest man Aliko Dangote, Bua Sugar Refinery and Golden Sugar Company were the only firms allowed to import sugar and would have access to dollars from official dealers.

The central bank justified its decision by saying the three firms, while still falling short of meeting demand, had made "reasonable progress" in producing refined sugar locally, but said they would still have to seek permission for purchases.

"Authorised dealers shall not open Forms M or access foreign exchange in the Nigerian foreign exchange market for any company or the three listed above for the importation of sugar without prior and express approval of the Central Bank of Nigeria," the bank said, referring to the mandatory statutory document that all importers of goods into Nigeria are required to complete.

The move could effectively create an oligopoly in the sugar importing business as other companies will not have access to dollars from official dealers.

Africa's most populous country, and its biggest economy, relies on imports to feed its 200 million people. The central bank restricted access in 2015 to foreign exchange for 41 items it says can be produced locally, and has gradually added to the list since then.

(Writing by MacDonald Dzirutwe, Editing by Kirsten Donovan)

By Camillus Eboh