More than $21 million worth of cocaine has turned up in boxes of bananas delivered to Aldi supermarkets in and around the German capital Berlin, police say.

Staff working at 14 Aldi supermarkets found the latest stashes of narcotics tucked inside fruit deliveries from Colombia.

Police spokesman Stefan Redlich told AFP authorities believed the drug ended up at the stores by accident.

"Apparently there was a logistical mistake somewhere along the line," he said, adding that investigators were now trying to determine their intended destination.

Mr Redlich said the 386-kilogram shipment was the biggest single cocaine find in the history of Berlin.

It is the second time in less than four months that a huge haul of cocaine has turned up in banana boxes at the discount chain's stores in Berlin.

In January 2014, Aldi workers discovered 140 kilograms of the drug, worth around $6.7 million, also hidden in crates of bananas.

The bananas came from Colombia on a shipment to Hamburg and the police believed the cocaine was sent to Aldi by mistake, according to German media reports.

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AFP