The government of Colombian President Juan Manuel Santos is preparing legislation that will set "personal dose" amounts for drugs that will allow for their possession without the possibility of arrest or prosecution, the Bogota newspaper El Tiempo reported Tuesday. The decriminalization legislation could be presented as early this week, the newspaper said in its exclusive report.

Colombia was the first Latin American country to decriminalize drug possession after a ruling by its Constitutional Court in 1994. But during the presidency Santos' predecessor, Alvaro Uribe, the government amended the constitution to criminalize drug use, effectively re-criminalizing drug possession.

Last year, the Colombian Supreme Court threw out Uribe's changes, ruling that the possession of small quantities of drugs for personal use was a constitutional right. This pending legislation recognizes last year's ruling and actualizes it by setting the "personal dose" amounts.

The 56-page document seen by El Tiempo sets the "personal dose" amount at five grams for marijuana and one gram for cocaine. It also sets "personal dose" amounts of 200 milligrams, or three pills, for amphetamine-type stimulants, such as methamphetamine and MDMA.

The five gram limit for marijuana is only one quarter the amount originally decriminalized, and has led some in Colombia to worry that it is too low.

"More consumers, for example, a young man traveling to a farm who carries more than five grams (hardly more than three or four joints) could be prosecuted as drug traffickers," warned Julian Quintero, director of Social Action, a group that works with young drug users.

The move by the Santos government comes as Santos prepares to lead a discussion on drug legalization and other alternatives to prohibition at the forthcoming Summit of the Americas in Cartagena next month. Pressure for serious discussions of legalization and its alternatives has been building in the region in recent weeks.