A ferry company has urged UK and French authorities to ensure there is no repeat of the huge delays at Dover.
Some people were forced to wait for 15 hours on gridlocked roads to reach the Kent port over the weekend.
Helen Deeble, chief executive of P&O Ferries, said holidaymakers were delayed for "completely unacceptable lengths of time" and insisted the situation "must never be allowed to happen again".
She said: "Increased security checks at the border are completely understandable but the French authorities must provide adequate numbers of staff to ensure that these checks can be processed quickly and efficiently.
"The failure to do so at the weekend was the primary cause of the delays."
Ms Deeble insisted that P&O Ferries did "everything we could to keep passengers moving" by providing extra sailings and more staff.
"We would nevertheless like to apologise to the passengers whose holidays were affected and assure them that we will be talking to the British and French authorities this week to ensure that there is no repetition of this disruption," she added.
Holidaymakers faced hours on gridlocked roads near Dover this weekend as some spent the night in their cars as they tried in vain to get to the port.
At one stage there were 12-mile tailbacks.
Delays for travellers heading towards the Channel crossing have eased but motorists have been warned to expect some disruption for weeks to come.
The head of the port of Calais said he is "ashamed" about the congestion.
Jean-Marc Puissesseau, president of the Cote d'Opale Chamber of Commerce, which runs the port of Calais, insisted he would complain to the French authorities about the failure to prepare for increased border checks.
Mr Puissesseau told BBC Radio 4's Today show: "I am very ashamed of this situation.
"I am so sorry for the British passengers starting their holiday with so long wait because of control."
He added: "When we know that there will be big traffic, as it was yesterday because it was starting holidays, it should be organised.
"And if the French police is obliged now to control because of all the terrorism we are facing, I can understand it but what I cannot understand is that they don't put enough policeman to control.
"I can tell you when I finish the call with you I will call the Home Office and tell them it is unacceptable."
Asked whether the delays could be revenge for the Brexit vote, he said "I hope not".
He added that he will "make so big pressure" that the delays should not happen again.
Police said the disruption was down to a "vast volume of holiday traffic" coupled with delays caused by heightened security at the border in the wake of terror attacks.
Increased checks were put in place by French authorities at the port but questions have been raised about staffing levels to deal with the huge number of people travelling at this time.
UK Border Force officials have since been drafted in to work with French border police.