Somchai Sawasdipol said the first tests would be conducted on air-conditioning and lighting systems, passenger check-in counters and the operation of CTX bomb scanners. Those tests and others will continue until the opening, now set for September 28.

Somchai brushed aside concerns raised recently by the International Air Transport Association (IATA), which urged Thailand to conduct full operation tests for at least six months before the opening date, as the new airport is using advanced information technology to link every system. System failure would be costly and embarrassing, an IATA official was quoted as saying two weeks ago.

"Don't worry, we started testing some systems since early this year and we will be ready by September," Somchai said. "Hong Kong and Kuala Lumpur had problems [when opening international airports in 1998] because officials were not familiar with the new facilities, but our officials will be given full training."

However, some officials at Don Muang Airport expressed doubts about the safety of the training regime, because many technicians and managers have had to leave their responsibilities at Don Muang behind to participate in the training at the new airport.

"I make my staff sign their names when they go to the airport in case something screws up here," said an official at Don Muang who asked not to be named.

The new airport is using personnel and equipment from outside sources for 47 jobs, including cleaners and security guards, the source said. He said contractors at the new airport had added Saturday as a work day in their attempts to have everything in order by opening day.

He said decoration and the setting up of duty-free shops were among the tasks requiring the extra day.

Local airlines are scheduled to make test take-offs and landings on July 29, Somchai said. It will then be determined if international carriers will be required to take similar tests.