Nearly five tonnes of cocaine have been seized in what customs officers say is one of the biggest shipments of drugs ever intercepted on its way to the Netherlands.

The 4,830 kilos of drugs, with an estimated street value of €250 million, were hidden in two containers filled with electric magnets being transported from Ecuador.

Customs officers picked up the unusual cargo when the containers were scanned in Rotterdam on January 8 and 9. The shipment was tracked to a company in Moerdijk, Noord-Brabant, where the magnets were inspected and the cocaine recovered.

Three people were arrested at the scene, including a 52-year-old man from Sliedrecht who made his first appearance before a magistrate on Wednesday. He has been remanded in custody for 14 days. The other two suspects were released.

The investigation is being carried out by the Hit and Run Cargo (HARC) team, which specialises in large-scale criminal operations around Rotterdam harbour.

A spokesman said the drugs had been destroyed and more arrests could follow.

Moerdijk municipal council will decide whether to take further steps, such as closing the business premises where the drugs were found, after reviewing a report from the prosecution service.