Robusta coffee exports from Cameroon more than doubled year-on-year in the month of April, statistics from the sector's regulator showed on Tuesday.

According to the National Cocoa and Coffee Board (NCCB) data, Cameroon shipped 7,575 tonnes in April, a sharp increase from 984 tonnes in the previous month and from 2,622 tonnes in April 2014. It did not give reasons for the increase in exports.

Seven firms exported robusta beans during the period with Olam Cam, a local unit of Singapore's Olam International topping the chart with 6,359 tonnes, followed by UTI with 540 tonnes and Nealiko with 378 tonnes, NCCB said.

Some 559 tonnes of arabica coffee were also shipped during the month, from 157 tonnes in March and from 232 tonnes in April a year ago, bringing the total since the start of the season last October 1 to 965 tonnes.

Cameroon is one of the few countries in Africa that grows both arabica and robusta coffee, with the former in the North-West and West regions and the latter in the West, South-West, Littoral, Centre, South, East and Adamawa regions.

The arabica coffee season runs from October 1 to September 30 and robusta coffee season from December 1 to November 30.