As many as 1.5 million children are working on cocoa farms in the Ivory Coast and Ghana, the world's top two producers, despite more than 10 years of efforts to reduce child labor, the International Labor Rights Forum (ILRF) said in a report.

The report, released on Wednesday, highlights how far the cocoa and chocolate industry still has to go to meet global standards as consumers increasingly demand that the production of cocoa, the main ingredient in chocolate, not include child labor.

"After more than a decade of effort to reduce child labor on cocoa farms in West Africa, child trafficking continues to plague the region," the report stated.

Concern about a supply deficit by 2020, due to falling yields and rising demand, caused chocolate companies such as Barry Callebaut, Mars Incorporated, Mondelez International and Hershey Co to increase their sustainability efforts to ensure long-term supplies.

They are spending millions of dollars to help improve cocoa farmers' lives by educating them on improving farm productivity, building schools and certifying their beans, but these efforts do not always target poverty, the root cause of child labor, the ILRF said.

The number of child laborers in the cocoa sector of Ivory Coast and Ghana, which produce about 60 percent of the world's cocoa, are estimated at 500,000 to 1.5 million.

The minimum legal age to enter the labor market in Ghana is 16 years old, while it's 14 years in Ivory Coast. Both countries prohibit the use of child labor for hazardous work, which includes jobs that are physically dangerous.

Nearly all the types of labor involved in cocoa farming have been identified as the "worst forms of child labor" by the governments of both Ghana and Ivory Coast, meaning children under 18-years-old should not do this work, the report noted.

"Trafficked children are often abused by landowners and are rarely paid," the report stated.

Though there are multiple certification systems in place that aim to improve farmer incomes while providing transparency to chocolate companies, the premiums paid "are not significant enough to raise farmers out of poverty", the report said.

Many cocoa farming families in Ivory Coast and Ghana make roughly $2 per day, around the international poverty line, making it difficult for them to pay hired laborers to harvest the crop at the legally required minimum wage, fueling the need for child labor, the ILRF said.