A CCTV camera has captured a man calmly pushing a woman on rail tracks at a Hong Kong train station, then walking away in cold blood.

The incident, since widely shared on social media, took place at the Yuen Long station of Hong Kong's Light Rail system.

The culprit is seen walking along the platform behind the victim, who is waving to someone on the other side of the tracks. The man then shoves her in the back, causing her to fall off the platform, and walk away without breaking stride.

Luckily for the victim, working as a cleaner at the station, no train was passing by at the time of the incident. Still, the footage shows her fall hard on her face from the height of the platform. According to a police spokesperson cited by South China Morning Post, she received injuries to her jaw and was taken to hospital.

Police arrested the man near the train station on suspicion of assault that resulted in bodily harm.