Colombia's Justice Minister, Ruth Stella Correa, has said a new drugs bill would legalise the personal use of synthetic drugs, such as ecstasy.
The proposal would replace current laws, which ban cocaine and marijuana, although people are not prosecuted for possessing small amounts.
A spokesman for the country's Green Party has expressed support for the government's plan.
"The problem in Colombia is a problem with soft drugs: marijuana and cocaine. The curse of drug trafficking depends fundamentally on cocaine and the decriminalisation in the world will end this business," senator Roy Barreras told Caracol Radio station.