Yves Brahima Kone, who leads the cocoa and coffee regulator, said the season's slow start would likely persist through March, with pods and flowers developing much slower than in previous years following a lacklustre rainy season.
"December is usually the month when most of the cocoa is exported, but arrivals are down 12-13% compared to the same period last year," Kone said told Reuters. "The trend is not going to be reversed."
Ivory Coast is currently in its main October-to-March cocoa crop season, the largest of the West African country's two annual harvests, and December is typically the highest-exporting month.
But port arrival figures at the beginning of the month showed a 10% decline from the same period last season, and exporters estimated this week that production had declined around 8%, based on truck counts.
More than a dozen farmers contacted by Reuters echoed Kone's pessimism, adding the trend would likely worsen as farmers scramble to sell as many beans as possible ahead of the Christmas holiday.
"I am more than worried because I have nothing left on the trees to cut and sell in January. I have already cut everything and there are only a few green pods left," said Alfred Kouadio, who runs a seven-hectare cocoa farm in Daloa.
(Reporting by Ange Aboa; Editing by Cooper Inveen and Mark Potter)
By Ange Aboa