The B744 aircraft arrived from the United Arab Emirates and "deviated from the northern runway after landing and ended up in the sea", according to the Hong Kong Civil Aviation Authority in a press release.
"Preliminary information shows that the four crew members on board were rescued and taken to hospital, while two ground staff were affected and fell into the sea", the authority writes.
The plane is believed to have collided with a ground vehicle that also fell into the sea, according to the authorities.
A man on board the ground vehicle, 30 years old, was confirmed dead at the scene, while another man, 41 years old, died after being taken to hospital.
The airport's northern runway was temporarily closed on Monday morning, while the two other runways remained in operation.
Corrected: In an earlier version of the text, there was an incorrect description of the aircraft in the image text.