Police and other investigators have seized a consignment of 1.5 tonnes of heroin packed in a container of Himalayan salt which arrived at Rotterdam port from Pakistan, the public prosecution department said.

The haul was made on the basis of information supplied by the National Crime Agency in Britain.

In total, five people were arrested following a raid on a property in Etten-Leur two weeks ago. Two have since been released but three remain in custody.

The drugs had a street value of €45m, the public prosecution department said. The haul is the biggest single consignment of heroin ever seized in the Netherlands.

No further information, including the eventual destination of the drugs, is being given in the ‘interests of the investigation’, the department said.