Rescuers aided by experts sent by the central government were rushing to search for signs of life and haul away stones and rocks, part of a 100,000 cubic meter (3.5 million cubic feet) mountain of displaced rubble that buried an office building and the construction workers' living area early Sunday.
More than 600 rescuers, including firefighters and police, were searching for the missing and attempting to clear sections of roads leading to the site that had been made impassable by mudslides and flooding, hindering efforts to get heavy machinery through.
The project in mountainous Taining county in Fujian province is an extension of the Chitan hydropower station, an affiliate of state-owned Huadian Fuxin Energy Ltd., and was expected to begin operations in August 2017.
An official at the county department, who gave only his surname, Wei, said by phone that the cause of the landslide was still unclear, but that the area had seen rainfall in the past few days, AP reported.
Heavy rain has affected much of southern China since Wednesday, triggering floods and landslides, disrupting transport, and destroying crops.