Colombia's new president Gustavo Petro has vowed to transfer assets seized from drug traffickers and other criminals to needy communities in the violence- and inequality-plagued country.

Petro, Colombia's first leftist president, said criminal assets "of an agrarian nature" should be made available to small farmers through cheap leases that would allow them to raise profitable crops.

Other assets could be used for the construction of housing and other projects that encourage a "social economy," he said Wednesday at an event in Villavicencio in central Colombia.

Criminals, Petro said, hold "billions of pesos... in all kinds of assets: luxury apartments, luxury houses, land, money, jewels, emeralds, gold, art, etc. All this can serve a social function."

The president added: "The directive we have given is that these goods be put at the service of the people."

To this end, Petro said he would transform the ASE, a government agency that manages, sells and leases assets seized from criminals.

The ASE, he said, became part of the problem with "enormous corruption processes" in which assets were returned to their original owners or ended up in the hands of the political class.

Petro, a 62-year-old former guerrilla and mayor, won June elections after promising profound reforms in a country beset by deep economic inequality and drug violence.

He has vowed to raise taxes on the rich, invest in health care and education, suspend oil exploration and redistribute unproductive land to boost food production.

The new president also wishes to initiate disarmament talks with the National Liberation Army (ELN) battling dissidents of the disbanded FARC guerrilla movement and cartels for control of drug fields, illegal gold mines and lucrative smuggling routes in the world's main cocaine producer.