Six men have been arrested for their role in attempts to smuggle over one tonne of pure heroin into the Netherlands from Iran.

The arrests were made following the discovery of the heroin hidden in baking machinery in a container at Antwerp port on Monday.

Police monitored the container as it was shipped on to Heijen in Limburg. There two men aged 39 and 41, both from Amsterdam, were arrested as they tried to open the container contents. A third man from Sittard was arrested in his car.

Later, three other men were arrested in Rotterdam. They worked for the company which had transported the container from Antwerp to Heijen, police said.

The street value of the haul, put at 1,137 kilos, is estimated at €34m if uncut. If cut with other substances, the value could be as high as €68m, police said.

Further arrests have not been ruled out and the investigation is continuing.