Lorries will be held on the coastbound carriageway of the motorway in a bid to keep the country's roads free of traffic, while "tourist traffic" is being advised to use the A2/M2.
Ferry services were badly-affected and, while Eurotunnel was beginning to run a normal service by early afternoon, truckers were left at the mercy of migrants hoping for a ride across the Channel.
A Port of Dover Spokesman said: "Customers are advised to contact their chosen ferry operator before travelling and consult the Port of Dover website or Twitter account for the latest travel information".
Around 400 ferry employees are staging a wildcat strike over fears they will lose their jobs next month as part of a restructure at Calais.
Industrial action by MyFerryLink workers saw blockades at both the Port of Calais and the Channel Tunnel in Coquelles, leading to a backlog of lorries on the M20 which were unable to cross the Channel.
Kent Police said the industrial action is set to last until this evening.
He told KentOnline: "I am extremely disappointed that Calais is on strike again".
"Although we will collectively seek to improve the operational efficiency of the new traffic management system, at this time, the most important issue is the safety of people using the A20".
It is understood that the traffic light system at the Western Heights roundabout will be used to control the traffic flow into Dover and through to Dover Eastern Docks.
Lorries heading for Calais via Dover's Eastern Docks.
There are also delays for freight on Eurotunnel and DFDS routes to Dunkirk.
A statement by the company today said: "We would like to inform you that our service is presently disrupted due to an incident on the terminal which is in the process of being resolved".