The Port of Dover has said that “due to national industrial action in France, services to and from Calais will be suspended from 7am”.
P&O Ferries said it has produced an “optimised” sailing schedule in light of the 24-hour strike – known as the National Day of Action in France.
The ferry company also warned “due to the lack of details”, it “cannot anticipate the level of disruption” that could still hit its changed sailing schedule.
The Port of Dover said it “is still open with services to Dunkirk running as normal”, but travellers should expect it and the local road network around Dover “will be busier than usual”.
In a statement, the company added: “Please plan ahead, allowing extra time for your journey and traffic systems that are in place to minimise delays.
“Calais sailings are expected to resume at approximately 2pm UTC from Dover.”
P&O Ferries said: “We have received information of a National Day of Action in France planned to last over a 24-hour period, starting on the 19th January 2023.
“It is expected that this action will affect multiple outlets and services throughout France.”
The company added: “Due to the lack of details, we cannot anticipate the level of disruption this will have to our optimised schedule, and it is possible that our wider operations could be affected throughout the day.
“Please be assured that we will attempt to limit this disruption wherever possible however, if your journey is not essential, we do advise that you rearrange your travel to an alternative date.”
Eurostar said its services would also be affected by the general strike in France, and it would be running a “revised timetable” on Thursday and Friday.
Passengers have been told to check if their train has been cancelled.
Trains will grind to a halt in France on Thursday, classrooms will shut and businesses disrupted as workers walk off their jobs in an attempt to derail a planned pension reform that would see the retirement age pushed up by two years to 64.