Irish Ferries has said it is working through customer calls as quickly as possible following the cancellation of all summer sailings from Dublin to France on its new WB Yeats ship.
Almost 20,000 people who were due to travel on the ship between 30 July and 17 September learned yesterday that they would have to make alternative arrangements.
A spokeswoman for Irish Ferries said it can accommodate up to 90% of affected passengers on the Oscar Wilde, which sails from Rosslare to Cherbourg.
But it said the departure dates may not be on the same dates and will have to be before or after original bookings.
A small number of passengers will also be re-booked on the Epsilon, which sails from Dublin to France at weekends.
Irish Ferries is also offering a land-bridge option where customers can sail to the UK and travel from there to France.
The company said it expects that it will take "about the same time" as the 18 hour sailing on the WB Yeats and the company will compensate passengers for their fuel costs
But it said it will not reimburse people if they need to book accommodation as part of this option.
It said that if customers require a refund that will be processed but it could take between a week and ten days depending on the payment method.
Irish Ferries said it dealt with a high volume of customer calls today.
The company had already cancelled July's sailings on the WB Yeats but was hoping August bookings could be fulfilled.
Irish Travel Agents Association President John Spollen said that only people booked on the WB Yeats should call the helpline and no other vessels are affected.