AMSTERDAM – The Dutch government’s plan to stop tourists from buying marijuana was apparently set back Wednesday after a key decision by the country’s top legal advisory body.

The Cabinet wants to curtail the country’s liberal marijuana policy to address problems caused by an estimated 3.9 million French, German and Belgian buyers who drive across the Dutch border annually to purchase the drug. It also wants to crack down on organized criminal gangs it says control the marijuana farming industry.

The Council of State ruled on a 2006 ordinance by the southern border city of Maastricht barring foreigners from “coffee shops,” where cannabis is openly sold.

The council said Maastricht had overstepped its authority, because selling marijuana is already theoretically illegal in the Netherlands, by national law — even though under the country’s tolerance policy police don’t prosecute people for possessing small amounts.

“Given this absolute ban laid down in law, in a formal sense there’s no room for a municipality to further regulate the sale of marijuana and hash by its own ordinances,” the ruling said.

The ruling also said that barring nonresidents from buying weed would not be unconstitutional discrimination — if done at a national level. It’s not clear whether that means the country’s drug laws would have to be amended.

Reactions to the ruling were mixed.

Justice Ministry spokesman Wiebe Alkema said the government is convinced the ruling won’t prevent it from its preferred solution: forcing cannabis buyers to obtain a “weed pass” in order to purchase marijuana. Coffee shops would issue the passes, similar to gym membership cards, only to people who can present a Dutch passport or resident visa, making tourists ineligible.

Critics say such a pass would violate privacy laws, and would be unworkable in practice.

Alkema said he couldn’t say yet whether the government would seek to change the law. “We’re looking at the possibilities,” he said.

The city of Amsterdam opposes the pass plan, arguing that tourists who visit and smoke weed usually stay several nights and boost the city’s economy.