Belgian police have discovered nearly 700 kilogrammes of cocaine in the back of a truck stopped in a freeway rest area near the port city of Antwerp.

The 46-year-old Bulgarian driver of the truck was arrested and is custody following the seizure made late Friday, prosecutors said on Sunday.

Police found the 698 kilogrammes of cocaine stuffed inside sports bags in the truck's container, according to a statement from the Antwerp prosecutors' office.

"The drugs will be destroyed as quickly as possible," it added.

Major gateway to Europe

Antwerp's port is one of the major gateways for cocaine smuggled in from South America to reach the European market, and drug busts in and around the vast facility occur frequently.

An unprecedented 110 tonnes of the illegal drug were seized at the port last year.