"The truck-and-trailer most probably served as a storage facility for an ecstasy laboratory," a police statement said.
Agents had on Thursday received a tip-off that a truck had been parked "for a while" in a parking lot in the country's southwest that was "hidden from the road".
Inside, police discovered 100 bottles of hydrogen, 15 tonnes of caustic soda and 3,000 litres of excipients such as methylamine, acetone and dichloromethane, estimated to worth several hundreds-of-thousands of euros.
Police did not mention arrests but have launched a probe to try and trace the truck's origin and destination, noting that it was registered in The Netherlands.
Law enforcement officials have in recent years have stepped up their focus on the southern Dutch provinces of Zeeland, Noord Brabant and Limburg which have seen an influx of organised crime -- particularly drug gangs -- from other provinces.
The region is close to Rotterdam, Europe's largest port, as well as to Antwerp in Belgium, both seen as major drug entry points into the continent.
Last year, a European Union report said ecstasy, once the drug of choice at rave parties in the 1990s, is back in favour and finding a wider market this time around.