"Different rules have resulted in passengers being unsure what items and quantities are allowed to be taken on board aircraft, whether they are allowed to transit with their duty-free goods and when these measures will be relaxed," said Albert Tjoeng, the IATA's manager for corporate communications in the Asia-Pacific.

This confusion has also resulted in security screening taking longer and passengers are "inconvenienced" when having to part with their possessions.

This is resulting in flight delays and higher incidences of missed connections, Tjoeng said in a statement. Also, more baggage having to go into aircraft holds is putting baggage screening and handling systems under stress.

This has resulted in more frequent equipment breakdowns and a higher requirement for preventive maintenance, leading to operational difficulties for the air carriers and uncertainty for passengers.

Airlines are also being affected financially by the varying requirements. Not only are they losing valuable revenue from duty-free sales, they may also have to pay higher airport charges as airport operators' income from duty-free sales fall.

The IATA statement says that effective security does not have to be inconvenient security. Association officials have been working with the International Civil Aviation Organisation and Airport Council International on guidelines for the screening of liquids taken on board aircraft.

"Harmonisation will help reduce confusion and inconvenience for passengers. Equally important is effective communication on regulations, whether they are imposed by governments, airports or airlines, in order to minimise confusion and inconvenience to the travelling public," the statement said.

Suchat Sritama

The Nation