A security guard was killed and another injured in a five-hour hostage ordeal during a robbery at Dinale power station near Brits on Wednesday, North West police said.

"The robbers broke into the station shortly after midnight and stole electrical cable valued at R100 000," Constable Tumelo Menyatso said.

After the five armed men gained entry to the premises, they held the two guards, aged 28 and 31 hostage, while they cut the cables.

"They shot the one in the stomach and assaulted the other. After the robbers fled, the injured guard called for help at about 5am."

The injured man was taken to Brits Medi-Clinic.

The power station supplies power to Mothotlung and surrounding areas.