"The Dutch navy found 6,000 kilogrammes of cannabis during a routine check on the fishing boat Caribbean Soul," it said in a statement issued in The Hague.
The cannabis was discovered late last week after a US Coast Guard plane spotted the boat as it sailed from Jamaica to Guyana.
It was intercepted by the Dutch ship Zeeland, stationed to patrol the area which includes parts of the Kingdom of the Netherlands -- Aruba, Curacao and Sint Maarten.
Drug seizures, usually cocaine, regularly take place in the Caribbean Sea.
Until last week the largest drug haul by the Dutch navy was in 2008, when it snatched 4,2 tonnes of cocaine in the region, Dutch media reported.
More than 10 tonnes of cocaine were seized in the area in 2013 as a result of international collaboration, Dutch news agency ANP said.