Dutch police found and demolished 151 drugs labs last year, compared with just over 100 in 2022, but busted fewer marijuana plantations, new figures show.

They also found 191 dump sites where drugs gangs had left empty barrels of chemicals in woods or roadside verges. That is up 25% on a year ago.

Zuid-Holland and Noord Brabant remain the most popular locations for gangs to manufacture synthetic drugs. In Zuid-Holland, police found 40 labs, most of which were used to cut cocaine and heroin, the drugs having arrived in the country via Rotterdam port.

The number of labs where cocaine is processed remained stable but police found 10 labs where heroin was being made ready for sale, up from two in 2022.

And the number of synthetic drugs labs soared 50% to 125, including 32 locations where MDMA was produced and 29 for methamphetamine.

Combi-labs are also on the rise as criminals switch between drugs, depending on demand, police spokesman Willem Woelders said.

At the same time, police dismantled fewer marijuana plantations last year – 1,230 as opposed to 1,604 in 2022. Most were found in Limburg, and the industry appears to have shifted away from the east of the country.

“This is because local gang leaders are changing their approach, and placing more emphasis on cocaine or synthetic drugs than cannabis,” Woelders said. “There are also signs that more cannabis is being imported from abroad, reducing the need for criminal domestic production.”

Drugs labs also pose a danger to others because of the risk of explosions. Earlier this year, three people were killed in a blast in a lock-up in a Rotterdam block of flats where cocaine was being “washed”.