The government has conceded post-Brexit passport controls at Dover led to chaotic scenes at the port at the weekend.
Thousands of passengers were left facing long delays and ruined plans because of processing times at the ferry terminal.
Now Downing Street has admitted French checks have to be sped up.
Fears are growing there will be similar problems over the long bank holiday weekend.
Currently, each passport has to be checked and manually stamped as passengers leave the UK.
But a high volume of coaches leaving Britain – many with children on board – played a role in days of chaotic travel queues at Dover because each can take up to 20 minutes to process.
Customers suffered 12-hour queues for ferries from Dover.
While Home Secretary Suella Braverman said it was “unfair” to characterise Brexit as the cause, Downing Street said the government was “in discussion” to speed up French passport checks.
Poor weather was also a factor in causing delays, said Number 10.
The spokesman told the BBC: “We recognise there are new processes in place – that’s why authorities were given a long time to prepare for the new checks, including during the transition period, of course.
“And we are in discussion with our French counterparts about how we can further improve the flow of traffic.”
Extra ferries laid on were insufficient to prevent queues at Dover increasing through much of Sunday.
The Port of Dover said coach bookings were 15% higher this Easter than what was expected.
On April 3, Port of Dover statement said: “The Port of Dover continued working round the clock with the ferry operators and border agencies to get coach passengers on their way and the backlog is now cleared.
“Along with the final coaches being processed through the port, all tourist cars and freight vehicles were also processed successfully.
“We continue to offer our sincere apologies to all those affected by the prolonged delays that have occurred over this weekend.
“We will be conducting a full review of our plans with the ferry operators early this week to ensure improvements are made ready for the forthcoming Easter weekend.”