A 66-year-old worker died on Saturday after he collapsed at the Chinese University of Hong Kong.
Police said the man fainted at around 2pm while he was carrying out window repair works at a building near New Asia Circle.
He was sent to Prince of Wales Hospital where he was later pronounced dead.
The Amber heat stress warning was issued during the incident.
Under the government's guidelines, workers involving moderate, heavy and very heavy physical workload should rest for 15, 30 and 45 minutes per hour respectively when the Amber warning is in force.