A huge backlog of lorries on the M20 could be cleared in 48 hours after the port of Calais reopened, P&O has said.
French union bosses have said the strike by ferry workers which caused the gridlock will remain suspended until at least Tuesday.
The Port of Dover said the disruption caused by the action was costing the UK at least £250m a day.
Thousands of lorries had been stuck in 30-mile queues on the Kent motorway, before finally moving on Thursday.
The French Transport Minister has promised further talks next Wednesday with French union Maritime Nord, which wants to safeguard 570 jobs.
Operation Stack, which saw roads closed for the lorries to park, will remain in place overnight, police said.
Port officials in Calais had been restricting entry to one ferry per hour.
But at 16:30 BST, P&O announced the French port had fully reopened and the ferry operator was moving back to its scheduled 25 sailings a day between Dover and Calais.
Highways England had predicted it would take until Monday to clear the backlog, even if the blockade were lifted immediately, but P&O chief executive Helen Deeble said the firm expected to carry lorries waiting as part of Operation Stack within 48 hours.
Prime Minister David Cameron and Home Secretary Theresa May have been in talks with their French counterparts.
As Mrs May met French interior minister Bernard Cazeneuve, Dover port chief executive Tim Waggott said every day of disruption was costing the UK economy at least £250m - a figure based on a study last year which found business through the port was worth £100bn a year.
Thousands of lorries remain stranded on the M20, with the coastbound carriageway shut for 26 miles, although the clear-up began to gather momentum after ferry services resumed.
Phase four of Operation Stack, in which the motorway was closed from Leeds Castle to Folkestone, was put in place for the first time on Wednesday.
The London-bound carriageway was also closed between Leeds Castle and Ashford, while non-freight traffic was advised to avoid the M20 and find alternative routes.
Disability charity Scope revealed it had cancelled its London-to-Paris fundraising bike ride this weekend because of the delays caused by the strike.
Action and reaction
- Home Secretary Theresa May met French counterpart Bernard Cazeneuve in Paris and Cabinet Minister Oliver Letwin was chairing a meeting of the government's emergency Cobra committee
- After meeting staff from port authorities and emergency services in Dover, Robert Goodwill, the transport minister responsible for ports and shipping, described the continuing disruption as "completely unacceptable"
- Damien Collins, MP for Folkestone and Hythe, said it was "an absolute disgrace" the French authorities had failed to take control, with strikers "illegally" starting fires on Eurotunnel property to add to the ferry disruption
- Tim Reardon, of the UK Council of Shipping, said the French government had failed in its duty to maintain law and order at the Port of Calais
- Conservative MEP Richard Ashworth urged the European Commission to put pressure on France to ensure cross-border links were safeguarded
- Richard Burnett, chief executive of the Road Haulage Association, called for the military to be deployed to break the strike, saying: "The time for talking around the table has passed."
Kent County Council continued to co-ordinate the distribution of water and food to stranded drivers and passengers.
But reporter Tomos Morgan, who was travelling with a lorry driver to Belgium, said those stranded midway between junctions had had to wait up to 12 hours for water.
Blockade in figures
- More than 18,000 bottles of water handed out
- About 6,500 meals provided to drivers and passengers
- Cost of providing food and water already more than £40,000 and expected to break £50,000 if blockade continues beyond weekend
- Queues of 4,600 lorries reduced to 3,500 by early afternoon, stretching back 30 miles
- Daily cost to UK economy estimated at £250m
The impact has been felt in surrounding areas, with man major north-south routes through Kent blocked for several days, leaving other roads unable to cope with the fallout.
Christine Drury, chairman of Westwell village Parish Council, said the current disruption was the biggest to the community so far because of the closure of both carriageways.
She said an overturned lorry on the A20, which was bearing the brunt of the extra traffic, caused "absolute bedlam" and effectively shut off the village, near Ashford,
But further chaos was averted when French air traffic controllers called off industrial action in a separate dispute.
French workers on MyFerryLink staged their wildcat strike to protest at the sale of the Eurotunnel-owned ships to Danish firm DFDS after a competition authority ruling.
DFDS officially took over the MyFerryLink service at midnight but striking workers are continuing to occupy two ships.
It continues to run to Dunkirk, with an additional ship diverted to the route to help accommodate heavy traffic.