Dozens of cannabis cafés across the Netherlands will be supplied by legal producers from 2021 as part of a four-year trial designed to eradicate the black market.

The country has long been renowned for its liberal drug laws and Amsterdam is a major tourist destination for marijuana aficionados. Cannabis can be sold legally over the counter at cafés across the Netherlands, but it is illegal to cultivate weed for recreational purposes.

The Netherlands does produce medical marijuana products and exports them to various European markets, but adult-use cultivation is outlawed. Yet the police force has historically turned a blind eye to the illicit growers that supply hundreds of cannabis café in various cities across the nation.

Now a trial will take place at 79 coffee shops in 10 towns, which will be supplied by legal cultivators between 2021 and 2025. If the trial proves successful, the Dutch government will expand it and push for a fully legal supply of marijuana for cafés.

The 10 towns taking part are Arnhem, Almere, Breda, Groningen, Heerlen, Hellevoetsluis, Maastricht, Nijmegen, Tilburg and Zaanstad. The four biggest Dutch cities – Amsterdam, Rotterdam, The Hague and Utrecht – will not take part, as the government decided it would be a logistical nightmare and potentially dangerous if all cafés in major cities abandoned their suppliers simultaneously.

The 79 coffee shops taking part represent 14% of the cannabis cafés in the Netherlands.

Justice minister Ferdinand Grapperhaus and health minister Bruno Bruins revealed the information at a press conference on Thursday. “Protecting consumer health and vulnerable groups is top priority, and the experiment will pay close attention to prevention and providing information,” said Grapperhaus.

Breda mayor Paul Depla, a leading advocate of the trial, said it could spell the end of an illogical and inconsistent policy that has seen legal coffee shops rely on illegal supply for more than four decades.

Regulated Dutch growers have lucrative export contracts and it remains to be seen what sort of price they will offer the cannabis cafés taking part in the trial. Coffee shop owners have warned that the price must be kept reasonable, or cannabis users will simply go direct to the black market themselves.