A worker died in hospital on Saturday after he was found unconscious at the site of the West New Territories Landfill Extension.
The Environmental Protection Department said the 64-year-old man's family contacted the site supervisor at around 5:30pm on Friday after he did not return home from work.
They said that the worker, who was hired by the sub-contractor for site formation works, was later found unconscious on the ground of the site platform after staff checked the CCTV and patrolled the site.
He was then sent to Tuen Mun Hospital where he was later pronounced dead.
Samuel Chui, the department's director, extended his condolences to the deceased man's family, adding that the department is very concerned about the incident.
The department has instructed the contractor to submit a report on the accident within seven days, and to cooperate with the police and other departments in an investigation.