UK holidaymakers fear they could be banned from future trips to EU nations because under-pressure police aren't processing their passports properly.
Concerned passengers travelling to the Balearic Islands have claimed have not had their documents exit-stamped on several occasions in recent months.
Under post-Brexit rules, UK passport holders must have their travel documents stamped on arrival and departure from all EU-Schengen zone nations, Wales Online reports.
The rule is to ensure strict quotes on the number of days non-EU residents spend in the bloc are kept to.
One passenger reported having two entry stamps still outstanding - even though one was from an April trip to Ibiza.
Have you had an issue with your passport? Email webtravel@reachplc.com
The passenger said: "I now have two 'un-closed' Spanish visits in my UK passport, making a nonsense of the 90-day rule, and running the risk of me being accused of overstaying my rolling 90 days’ allowance. Which I haven’t."
Another traveller on a flight from Bristol to Majorca claimed officials were only checking the status of around one-in-10 visitors arriving on the holiday island, with just three officers on duty to receive incoming passengers.
The Majorca resident said: "The lack of checking of documents was obvious. They checked about one-in-10 and let everyone else pass on through."
A journalist who visited Majorca, and did not get his passport stamped on departure, was held up for more than an hour at Frankfurt airport in Germany because it appeared he had exceeded his 90-day allowance in the previous 180 days.
He said: "Luckily I had documents confirmed I had left Majorca well before the end of the 90-day period. But it took time to convince the German police, leaving others I had travelled with waiting for me to be allowed entry into the country.
"Something needs to be organised to prevent this sort of confusion from arising again. Authorities in many locations appear totally unprepared for the volume of holidaymakers from the UK."
