Last year the area of coca cultivation expanded to a vast 204,000 hectares (504,100 acres). Colombia is already the world's largest cocaine producer.
It is the highest figure since the UN Office on Drugs and Crime (UNODC) began collecting such data in 2001.
Colombian President Gustavo Petro has called the war on drugs a failure.
Instead, the newly elected left-wing leader wants to regulate the industry and expand programmes to substitute illegal crops, BBC South America correspondent Katy Watson reports.
Most of Colombia's cocaine heads to Europe and the United States, which is the world's largest consumer of the drug.
For years Colombia has struggled to get farmers to move away from coca production, but promises to provide incentives and subsidies have not materialised, our correspondent says.
[…]Threat to biodiversity
The UNODC says coca cultivation continues to threaten Colombia's biodiversity, contributing to deforestation. About half the coca plantations are in special land management zones, including forest reserves.
Aerial spraying to get rid of the crops was suspended in 2015 after a court ruled that the herbicide used - glyphosate - could cause cancer and pollute the land.
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