France and Germany would shoot themselves - and Europe - in the foot by pressing for stepped-up border controls in the travel-free Schengen region, the senior UN tourism official said.
Countries should instead insist on more liberal travel rules or risk being left out of the revenue and jobs that tourists shower on popular travel destinations, said Taleb Rifai, secretary-general of the World Tourism Organisation (UNWTO).
France and Germany have proposed that Schengen countries get more leeway in extreme cases to suspend the pact, which permits visa-free travel across 26 EU and non-EU countries, to ensure tighter security within the European Union.
That would be the kiss of death, Rifai told reporters on the sidelines on a UN conference on crime.
"Let alone what France and Germany are asking - because it is going to hurt them more - the whole Schengen area has to look at itself... It is going to be very, very damaging."
EU states already have the power to allow the reintroduction of border controls for 30 days if there is a specific threat to security or public order.
"The Schengen zone is depriving itself of tremendous potential of more tourists (and) more benefits by actually insisting on procedures and formalities that belong to the 19th century," Rifai said.
He said his agency was already trying to raise awareness about how "primitive" many countries' visa rules were and would present a study on this to the next summit of Group of 20 leaders in Mexico in June.
With China set to become the world's biggest tourist supplier by 2016, other countries need to rethink whether they want to force many Chinese to travel - sometimes repeatedly - to distant consulates for interviews and then wait weeks or months to find out if they will get a visa, he said.
He cited the example of Turkey, which saw the number of tourists from Russia nearly double after it agreed in 2009 to grant them visas upon arrival.
Every 48 new tourist arrivals in Turkey create a new job there, as do every 43 arrivals in the United States, he added.