The port of Dover has been closed to all vehicle traffic leaving the UK for the next 48 hours.
France acted to halt lorry movements in the wake of fresh concerns over the spread of a new strain of coronavirus.
UK ministers and officials will discuss the move at the government’s Cobra emergency committee on Monday.
Transport Secretary Grant Shapps urged the public and hauliers not to travel to ports in Kent, saying “significant disruption” was likely in the area.
Kent Police has put Operation Stack into force on the M20 towards Dover to queue lorries caught up in the disruption.
The force said it had implemented the closure of the coast-bound carriageway of the motorway between Junctions 8 and 11 as a “contingency measure”.
The Department for Transport has said that Manston Airport in Kent is being readied to take up to 4,000 lorries to ease congestion in the county.
The Port of Dover is closed to traffic leaving the UK “until further notice” due to border restrictions in France, port authorities said in a statement.”
Both accompanied freight and passenger customers are asked not to travel to the port,” it said. “We understand that the restrictions will be in place for 48 hours from midnight.”
Freight coming to Britain from France will be allowed, but there are fears lorry drivers will not travel to avoid being stuck in the UK.