New Dutch laws to stub out the sale of cannabis to foreign dope tourists have kicked in - and was promptly breached by a prominent coffee shop in Maastricht.
"People, you can come inside without a cannabis card. We are open to everybody," Marc Josemans, owner of the Easy Going coffee shop in the southern Dutch city told his clientele on Tuesday as they lined up outside his place.
Josemans, who has been spearheading a pro-pot drive to get the new Dutch laws scrapped, opened his doors at around 11.15am (1915 AEST) to some 20 customers, at least two from Belgium and one from Germany.
"I think the cannabis card is discriminatory and trouble in the streets will grow in the weeks to come," Josemans told AFP as his customers bought the Dutch maximum legal quantity of five grams of marijuana before leaving.
"We prefer to smoke a joint," one customer, a 25-year-old woman from Liege in Belgium told AFP as she left the shop, adding: "If we can't do it legally in the Netherlands, we will do it illegally."
Famous for decades for its laid-back attitude toward marijuana, the Netherlands will now require so-called coffee shops in some regions to only sell to signed-up members who live in the country, not to foreign visitors.
The tougher rules, set to take effect nationwide from next year, effectively turn coffee shops into private clubs with no more than 2000 members, who must be over 18 and legal residents of the country.
Starting on Tuesday in three provinces, coffee shops must turn away those without the so-called "cannabis cards", which allow locals and foreigners living in the country to enter and light up.
A last-minute challenge seeking to declare the law discriminatory by coffee shop owners -- including in the Limburg, North-Brabant and Zeeland provinces on the Belgian and German borders -- failed last week.
On Tuesday, most of Maastricht's other 14 coffee shops remained closed in protest against the legislation, said Josemans, who is the chairman of the city's association of coffee shop owners.
Many local residents however have welcomed the change, saying they have had enough of traffic jams, nocturnal disturbances and drug pushers catering to the millions of foreign visitors drawn by the relaxed cannabis laws.
Maastricht, a popular destination for some 1.4 million "drug tourists" every year from Germany, France and Belgium, said last week it was ready to enforce the "weed-pass" legislation.
It said in a press release that from May 1 "Maastricht adjusts its policy on coffee shops" and warned that violators face administrative sanctions, including having their business shut down.
The centre-right government of Prime Minister Mark Rutte has for years prepared the ground for making the "cannabis card" obligatory when visiting one of the country's 670 licensed coffee shops.
Although cannabis is technically illegal in the Netherlands, the country in 1976 decriminalised possession of less than five grams of the substance under a so-called tolerance policy.
In neighbouring Belgium, Home Affairs Minister Joelle Milquet warned the country was ready to take action against drug tourists, saying: "Slipping in an illegal supply will not be tolerated in Belgium."
Dutch authorities have also set up large signs over the weekend announcing the ban under a slogan that read: "New rules, no drugs," while the police presence has been increased on both sides of the border.