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.
Chau said the technique was used in a strategic way without prejudice. 'It is not used on specific races or nationalities,' he said.
Company deputy director William Yeung said the technique had been in use since 2007 and all the airport security staff had completed the one-day training last year.
Giving an example of successful use of the technique, Yeung said three passengers behaving strangely were found to have drugs in their luggage. Another passenger seen acting nervously was found illegally carrying a pet turtle in hand baggage.
For the East Asian Games, to be held in Hong Kong from December 5, Chau said security staff were prepared to deal with any threat, even though the risk assessment for the event was only moderate.
Senior Superintendent Stephen Handley, assistant director of the company on secondment from the police, said about 3,000 Games participants, including athletes and VIPs, would come through the airport. 'We are closely looking at the threat level in order to ensure Hong Kong will not be a terrorist target,' he said.
Two Segway personal transporters will be used by airport security staff for a quick response to any incident in the terminals. The Segways, each costing about HK$70,000, help improve the security guards' visibility as they travel about half a metre above the ground.
Two Magshoe metal detectors, which can detect metal content in shoes without passengers removing them, will be also used.