Italian authorities have discovered €150m ($164m) worth of cocaine hidden on the Greek-owned Atlas, a Laskaridis Shipping bulker in Venice
Divers inspected the hull after officials studied plans of the ship, which had been subject to several searches since Tuesday.
The Guardia di Finanza reported that the 570 packages of cocaine weighing 850 kg were found stashed inside ventilation ducts.
The ship had left Santos in Brazil on 23 March and arrived in Venice on 17 April. The Laskaridis Shipping company has not yet commented.
Container ships are more usually targeted for drugs smuggling, but other vessels can also find themselves used unwittingly by gangs.
The seafarers on board have not been arrested, and investigations are ongoing.
