US chocolate giant Hershey is to source “100%-certified” cocoa for its global chocolate lines by 2020.

The company has also announced its intention to accelerate its programmes to help eliminate child labour in the cocoa regions in West Africa.

As the largest chocolate manufacturer in North America, Hershey claims its 2020 purchasing commitment will “significantly expand” the global supply of certified cocoa.

Cocoa will be verified through independent auditors to ensure it is grown in line with the highest internationally recognised standards for labour, environmental and better farming practices, the company said.

Hershey did not specify which certification scheme, such as Rainforest Alliance or Fairtrade, it will apply – if any. But it pointed to its announcement earlier this year that its Hershey’s Bliss chocolates would be Rainforest Alliance certified by the end of this year.

Chief executive JP Bilbrey said it was right for Hershey to address the economic and social issues affecting West Africa’s two million cocoa farmers and families.

“Expanding the use of certified cocoa across our iconic chocolate brands, while working with public and private partners, demonstrates Hershey’s responsible sourcing practices,” Bilbrey said.

Hershey – which has annual revenues of more than $6bn (£3.72bn) – would continue to support community-based projects such as village school construction and health programmes, he vowed. But the company did not specifically refer to a fair pricing element to the 2020 target.

Currently, less than 5% of the world’s cocoa supply is certified.