Europe's airport chief has issued a stark warning that he "doesn't know" how the continent's airports will "cope" with the massive delays triggered by a new EU border system as the peak holiday season approaches.

Stefan Schulte, president of European airports trade body ACI Europe, told an industry conference in Prague: "Passengers are queuing for hours at peak traffic times and I just do not know how we will be able to cope in the coming weeks with the expected increase in traffic."

The EU completed the rollout of its new Entry-Exit System (EES) earlier this year, which mandates that passengers from outside the bloc must register biometric data when entering and departing most European nations.

Earlier this month, the Express reported from Athens, where huge queues caused around 20 passengers to miss their flight to London Luton. The EES was not in operation, raising serious concerns about how the airport will manage once an extra hurdle is introduced.

The new arrangement has been held responsible for causing substantial delays and missed flights at numerous airports, although others have reported a smooth implementation.

Schulte urged politicians to "stop pretending [...] that EES is working just fine. It is not."

"We urgently need full flexibility for border control authorities to suspend the EES whenever needed to avoid further chaos – along with a rethink of those processes," he added.

"This is about showing respect and decency for those who chose to travel to the EU, and safeguarding our reputation as a welcoming and efficient destination."

The European Commission, which administers the EES, has indicated it will permit airports to suspend the new system under certain circumstances until September. The airports chief told the BBC's World at One that governments ought to intervene and suspend the EES, rather than allowing queues to build up while individual airports decide whether to take action.

The summer travel period will extend well beyond early September, Schulte cautioned, and could lead to the "complete collapse of the system".

Earlier this year, a row broke out over the system in Greece, where the tourism minister assured Britons that they would not be "burdened" by the new biometric checks.

However, the Greek Foreign Ministry subsequently denied that any such exemption existed, stating that it was not aware that "specific nationalities are temporarily exempt from the relevant procedure".

Last month, the UK chief of budget carrier Wizz Air advised passengers to allow at least three hours to clear the new system.

While some areas had experienced "seamless travel", Yvonne Moynihan noted there had been significant queues at "usual hotspots such as Spain, Portugal, France".