Six people died and six others were injured when a platform in a tunnel collapsed at an Eskom construction site near Ladysmith on Thursday.
"Eskom is saddened to announce that six people have been confirmed dead after an unfortunate incident that occurred … at Eskom's Ingula pumped storage construction site," it said in a statement.
"About 15 people were working in the tunnel when a working platform failed and left several people injured. A detailed investigation will be launched into the incident."
The parastatal said this happened around 9.15am.
IPSS medical response spokesman Marinus Nabal said six people were injured in the incident and were transported to hospital.
He said the body of one of the deceased was recovered and a search and rescue team were trying to recover the other five bodies.
The project, which is under construction, is expected to be finished next year and involves pumping water up the Drakensberg Mountains from the Braamhoek Dam to the Bedford Dam during off-peak hours, an elevation of about 470m.
Water is then to be released through the tunnels to flow down during peak hours, generating electricity. – Sapa