The court did not specify the quantity of cannabis a person can grow or use in private.
The state appealed to the Constitutional Court, which upheld the high court's findings.
In delivering the Constitutional Court's unanimous verdict, Deputy Chief Justice Raymond Zondo on Tuesday declared the law banning marijuana use in private by adults "is unconstitutional and therefore invalid".
In addition to this, parliament has been given two years to change sections of both the drug trafficking act and the medicine controls act.
"This Court must invoke its powers under s 172 (1) (b) of the Constitution to order a suspension of the declaration of invalidity for a realistic period to ensure Parliament may correct the defect".
The Constitutional Court of South has ruled that the consumption of dagga, limited to private personal use, is no longer a criminal offence. The legislature has been given 24 months to do so.
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It will still be a criminal offence to use cannabis in public and to sell or supply it.
Three cannabis users who had faced prosecution for using the drug brought the case, saying the ban "intrudes unjustifiably into their private spheres".
The beverage company made the confirmation while responding to a report from BNN Bloomberg that said it was in talks with Canada's Aurora Cannabis Inc.to develop drinks infused with cannabidiol (CBD), the non-psychoactive chemical found in marijuana. It held that the right to privacy extends beyond the boundaries of a home.
The court says it would be up to a police officer to decide if the amount of marijuana in someone's possession is for personal consumption or dealing. "Ultimately, it will be the court that will decide whether the person possessed the cannabis for personal consumption".
Judge Zondo also mentioned that the quality of cannabis would need to be taken into account when defining personal use.