Motorists and cross-Channel ferry operations faced disruption as a 24-hour strike by port control officers in northern France got under way today.
Kent Police urged hauliers and drivers to delay their journeys amid concern that industrial action at the ports of Calais and Boulogne could result in heavy freight and traffic delays in the county.
The stoppage means ferry traffic will be unable to berth at either of the two ports, and P&O and SeaFrance sailings to Calais will not be operating while the port is closed.
But police said Norfolkline will still operate sailings from Dover to Dunkirk, and sailings from Ramsgate will also be unaffected by the strike action.
Eurotunnel will continue to take freight and people who have already secured bookings, although services are still limited as a result of last month Channel Tunnel fire.
Police said that, on this occasion, Eurotunnel is only allowing account holders for freight to travel, while Eurostar services will be unaffected.
Kent Police this morning implemented phases one and two of Operation Stack, the tactic used to queue lorries on the M20 whenever there are problems with Channel crossings.
Assistant Chief Constable Allyn Thomas said: "It is unfortunate that we are facing this situation.
"The volume of freight travelling through Kent on its way to continental Europe is usually at its peak midweek, so the consequences of Calais being closed by this planned strike action, coupled with restricted shuttle services through the Channel Tunnel, create a potentially dire situation on the county's roads."Reuse content