All airport security staff have been trained in Israeli-style behaviour-recognition skills, and will scan crowds during the East Asian Games for suspicious activity.
This technique - also used at US airports including Boston's Logan International, from where two of the hijacked airliners used in the September 11 terrorist attacks took off - looks at how an individual behaves in an airport environment to determine if there is a threat.
Passengers displaying odd or abnormal behaviour such as sweating or nervousness during a security check, wearing a bulky coat on a hot day or taking photographs in unusual areas are noted by trained officers.
'This skill is a part of our multilevel defence, which is a good deterrent without causing inconvenience to the general public,' Sidney Chau Foo-cheong, executive director of Aviation Security Company, said.
The non-profit company, held jointly by the Airport Authority and the government, is in charge of about 3,000 security guards at the airport.
Security guards use the same technique when monitoring surveillance footage from restricted areas, including the departure gates.
Hong Kong's airport is the only one in Southeast Asia with all its security staff trained in the technique. The firm has also provided training for Beijing Capital International Airport.