The world's fifth largest cocoa producer shipped 3,043 tonnes of beans in April, down from 3,207 tonnes in March and 5,849 tonnes in the same month a year ago, the data showed.
The NCCB said 10 companies exported beans in April, up from seven in March.
Producam topped the list with 1,003 tonnes, followed by Olam Cam with 860 tonnes, and Ets Ndongo Essomba with 301 tonnes.
For the second consecutive month, Sic-Cacaos and Chocolaterie Confiserie du Cameroun (CHOCOCAM) made no purchases. Cameroon's cocoa season runs from Aug. 1 to July 31, with the main crop harvest period from October to January/February and the light crop harvest from April/May to July.
The crop is grown mainly in four regions, with the centre and southwest each accounting for 40 percent of national output, the south 15 percent and the east 5 percent.
Cultivation is also extending gradually to the northwest and west.
National output hit a record of 240,000 tonnes in the 2010/11 season before dropping to 220,000 tonnes in 2011/12 due to attacks by pests and diseases and a prolonged dry season.
It rose to 228,948 tonnes in 2012/13.