Ivory Coast and Ghana, the world's top two cocoa producers, have threatened to name and shame chocolate brands they say are undermining a scheme to pay cocoa farmers a decent income.

They introduced a premium scheme last year to help lift cocoa farmers out of poverty.

But a drop in demand for chocolate because of Covid-19 and an abundant harvest has caused a surplus of cocoa beans.

The two West African countries accuse buyers of demanding discounts and of refusing to pay another premium, which takes into account the quality of the cocoa beans.

"This amounts to robbing the consumers by collecting premium on bars of chocolate and then refusing to pay when buying cocoa beans," Joseph Boahen Aidoo, the chief executive of Ghana's cocoa regulator Cocobod, is quoted by the Reuters news agency as saying.