Chinese travelers going on duty-free buying frenzies at Narita International Airport are gumming up the works by causing delays to China-bound flights.

But the disruptions, while a headache for airline operations, are also a bonanza as Chinese travelers' deep pockets are helping to boost retail sales at the airport.

Flight delays are being caused as travelers require extra time to recheck their luggage after buying souvenirs in the duty-free areas that exceed the carry-on amounts. The airport's operating company has also taken to warning passengers about carry-on restrictions.