'It is not acceptable to penalise private conduct that does not cause danger or damage to third parties,' the decision said.

Cabinet chief Anibal Fernandez said Tuesday's ruling was 'the most the court can do', since it is up to Congress to amend the drug laws in a more fundamental way, as advocated by the administration of President Cristina Fernandez.

The Fernandez government seeks to combine a fairly broad decriminalisation of drug possession and consumption in favour of a focus on the illicit trade.

A joint study by the association Intercambios and the University of Buenos Aires found that more than 70 percent of the drug cases in Argentine courts involve simple possession for personal use.