The Dutch city of Utrecht wants cannabis smokers to grow their own marijuana in a cooperative, a move which would go against the Netherlands' drive to discourage soft drug use.
It also would be illegal, the government said.
The Netherlands has one of the most liberal soft drugs policies in Europe and the use of marijuana is legal but the mass cultivation of cannabis plants is illegal and controlled by criminal groups.
"We want to tackle this in the experiment. If you have some users grow the cannabis you remove it from the criminal and illegal scene," Utrecht's alderman Victor Everhardt told Dutch public broadcaster NOS on Thursday.
Utrecht is the Netherlands' fourth-largest city, about 50 km (30 miles) southwest of Amsterdam.
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By controlled cultivation, the quality also would be guaranteed and reduce health hazards, Everhardt said.
A Dutch citizen can grow a maximum of five cannabis plants at home for personal use, and the city wants weed users to unite in a cooperative.
The Dutch Ministry of Security and Justice said, however, the plan was illegal and would face prosecution if implemented.
"The soft drugs policy does not allow for the collection of plants and to grow, for instance, 500 plants," the ministry spokesman said.
For the past several years, the Netherlands has been cracking down on the use and sale of cannabis and hashish by closing down shops and limiting the sale to foreigners because of health effects and criminal activities linked to production.
