Operations of multinational companies with offices in Hong Kong have been hampered by severe emotional stress on senior executives since the disappearance of Malaysia Airlines flight MH370.
Some suffered emotional collapse and were unable to work or travel after learning that colleagues were on board the lost Boeing 777, a counselling charity said.
The affected staff members were among more than 100 employees of three companies in Hong Kong who sought help from the Post Crisis Counselling Network.
"Some of these senior executives collapsed emotionally," the network's executive director Timothy To Wing-ching said. "They couldn't work and the company's operations are affected."
To said the passenger list of the doomed aircraft included senior executives from the three companies so many of those seeking help were also at management level.
Some became afraid of taking flights and one fell physically ill when setting off on a business trip.
The network, which also helped people affected by the catastrophic Sichuan and Japan earthquakes, provides free counselling services, including office visits for group counselling.
An estimated 300 people from the three companies know the missing passengers and are suffering post-traumatic stress disorder.
To said some had yet to seek help.
To reach them and others affected by the plane's loss, including those distressed by news reports, the network yesterday started a special hotline - 51815501.
The network says staff of the three companies may be the tip of the iceberg with many other Hongkongers possibly knowing passengers on the flight.
To said people recovered from post-traumatic stress disorder when they were able to release their grief and the best way to help them was by listening to them.
There are two main types of sufferer - those who appear calm but are suppressing their emotions, and those who vent their emotions. It is usually easier for the latter to recover. Senior executives of large firms were usually rational and educated people and might belong to the suppressed type, To said.