Brazil's Supreme Court said Tuesday a majority of judges had voted to decriminalize possession of marijuana for personal use, after a lengthy and divisive trial.

Eight of the top court's 11 judges voted for small amounts of cannabis possession to remain an "illicit act" -- but one that is not punished by criminal proceedings.

The judges will still have to determine what quantity of marijuana will differentiate a casual user from a trafficker.

"We have a majority" to decide that "possession of cannabis for personal use is an illicit act" but not "of a criminal nature," said court president Luis Roberto Barroso.

The matter was taken to the Supreme Court by lawyers defending a prisoner who received an additional term for hiding three grams of cannabis in his cell.

The trial began in 2015 and has been interrupted on several occasions.

Brazil's current law, dating to 2006, considers it a crime to "acquire, possess or transport drugs without authorization." 

That law removed prison sentences for the crime, but did not clarify what quantity is deemed to be for personal use -- which carries lighter punishments like community service -- or when one is considered to be trafficking in the substance, which does carry a heavy prison term.

That interpretation was left up to police, prosecutors and trial judges.

In voting in favor of decriminalization in August, Supreme Court Judge Alexandre de Moraes said existing laws punish above all "young people, especially black people, who are treated as drug traffickers for possessing small amounts."

The issue is highly controversial in Brazil, where powerful conservative movements are firmly opposed to any decriminalization of marijuana.

In April, the conservative-majority Senate approved a bill which aims to make possessing any amount of drugs a constitutional offense.

This amendment will soon be debated in the lower house Chamber of Deputies.

Medicinal use of cannabis has also sparked debate, with patients forced to go to court to get permission for treatments based on CBD, the non-psychotropic molecule of cannabis, for certain severe forms of epilepsy. 

Multiple countries have decriminalized the recreational use of cannabis in recent years, waiving prison sentences for users, but those to legalize its use are rare.

Uruguay did so in 2013, and Germany this year became the biggest European Union country to legalize recreational cannabis, accompanied only by Malta and Luxembourg.