Cocoa farmers in Cote d'Ivoire on Thursday escalated a media campaign against multinational chocolate makers, threatening them with a boycott in a dispute overpayment.

Four major farmers' organizations, known by their initials FOPCC, ANACACI, APROPAM and FNFPCC, fired a verbal broadside after meeting with Cote d'Ivoire's commodities board, the Coffee Cacao Council (CCC).

"We will boycott the activities of all corporations which oppose the living income differential (LID)," they said, referring to a scheme of premium payments at the heart of the row.

Under the LID, multinationals pay a premium of $400 above market price for each tonne of cacao, the raw material for chocolate.

Millions of small farmers in Cote d'Ivoire and Ghana, which together grow 60 percent of the world's cacao, live in grinding poverty.

The heads of the four organizations said they were suspending their role in certifying that cacao meets ethical standards of sustainability and child labour — programmes that are a valuable image boost for chocolate makers in western markets. 

They even waved the threat of stopping growing cacao.

"It's a question of survival. We are ready to go right to the very end. We can put our cacao production on hold for a year or two and grow other crops," said Soro Penatirgue, president of the National Association of Cote d'Ivoire Agricultural Cooperatives, or ANACACI.

The show of defiance came three days after unprecedented public allegations against US confectionary titans Mars and Hershey.

The Ivorian and Ghanaian cocoa boards accused the two corporations of signing up for the LID but making purchases outside the system to avoid paying the premium — charges that both firms strongly denied.

The head of the CCC, Yves Kone, who attended Thursday's talks in the country's capital Yamoussoukro, gathering around 500 farmers' delegates, sought to ease the angry tone set by the growers.