Almost a third of companies who ship goods to Britain through the Netherlands have failed to complete the necessary paperwork for their trucks to embark on ferries after Brexit, the Dutch transport association TLN said on Wednesday.
"The registration is absolutely necessary, without it trucks will be sent away at terminals after Brexit," TLN spokesman Elmer de Bruin said.
The Netherlands is home to Europe's largest seaport in Rotterdam, making it a major hub for trade with Britain.
To keep the traffic across the North Sea flowing after Brexit, Dutch authorities have created a single customs platform where companies need to digitally register their shipments to be allowed onto ferry terminals.
De Bruin said about 70% of transport companies had properly registered for customs procedures but some 30% had not yet done so. Almost all unregistered companies are based outside the Netherlands, De Bruin said, citing Poland and Austria as examples.
Rotterdam port handles about 40 million tonnes of goods to and from Britain every year and has repeatedly warned about the consequences if Britain does not secure a negotiated withdrawal from the European Union, fearing massive traffic jams and a weakening of international trade.
Port authorities on Wednesday said they had created emergency overflow parking spaces for about 700 trucks, where drivers will get 24 hours to get their paperwork sorted.
Reporting by Bart Meijer