A Nespresso plant has been the scene of a huge drug bust, with police seizing more than 500kg of cocaine that was smuggled in a shipment of coffee beans.

Workers at Nestle's capsule-making factory in Romont, in the western canton of Fribourg, Switzerland, alerted authorities to "an undetermined white substance" found in the sacks of coffee beans delivered from Brazil.

Police analysis determined the substance was cocaine and commenced a search of the five shipping containers that had just arrived by train.

In a statement on Thursday, Fribourg police said the haul was determined to be more than 80 per cent pure with an estimated street value of more than 50 million Swiss francs ($78m).

"It appears that all of the drugs were destined for the European market," the statement read.

Their operation reportedly involved a large contingent of customs officers who secured the substance to protect it from cross-contamination – which, Nespresso said in an emailed statement, was successful.

"The substance in question did not come into contact with any of our products or production equipment used to make our products," Nespresso's statement said, Reuters reports.

"As a police investigation is underway, we cannot share more details. We want to reassure consumers that all our products are safe to consume."

- Georgina Noack, news.com.au