Strike action is being threatened at Eurotunnel over the bank holiday weekend in a row over pay.
French unions are demanding a sharp pay rise and may walk out at one of the busiest times of the year.
Eurotunnel has suspended bookings, but says it remains confident of being able to staff potentially all services should workers walk out.
A spokesman said: “We have been notified of possible strike action and are now taking all steps possible to mitigate any disruption should it go ahead.
“We are, for example, ensuring British train drivers will be available and we can send British staff to man the terminal in France if necessary. We would hope, even if action does take place, to still be able to offer a full service.
“However, we have taken the step to suspend bookings for the weekend.”
The company expects to issue a statement later today or tomorrow morning on the situation with regard the strike action.
French ferry firm SeaFrance says it has space available on all Dover-Calais sailings throughout the weekend.
“Passengers are advised to book as soon as possible as the company is already seeing an increase in bookings for the weekend,” the company said.
“SeaFrance advises customers who have booked a crossing this weekend to use the M2/A2 route to the Port of Dover to avoid potential delays as a result of the Eurotunnel strike action.”