KHAKASIA, August 29 (RIA Novosti) - Work to repair the Sayano-Shushenskaya hydroelectric station in south Siberia, following a tragic accident on August 17 that left 71 people dead, is to be carried out in three shifts, the acting CEO of RusHydro said on Saturday.

"At the current time, work is being carried out in two shifts, but it is highly likely that we will move to a three-shift working system," Vasily Zubakin said, adding that the reasoning behind the move was an influx of workers and the fact that the current 12-hour shifts were "extremely hard."

The disaster occurred during repair work to one of the plant's 10 hydroelectric generators. A surge of water shattered three of the turbines and flooded much of the plant.

Zubakin said that RusHydro planned to sign an additional agreement with the main contractor on September 1 to try and speed up the construction of a water sluice to take the strain off the main station at the plant.

He said that the most difficult work involved restoring the supports and concrete casing, which were severely damaged in the accident.

Locals believe the accident was caused by plant management seeking to produce as much electricity as possible without paying enough attention to the condition of the equipment, a charge dismissed by power plant representatives.

The prime minister of the republic of Khakasia, Viktor Zimin, said he was personally supervising the investigation and "no one is hiding anything."

RusHydro has said the damage could take up to two years to repair, and Energy Minister Sergei Shmatko estimated the cost could run to at least 40 billion rubles ($1.2 billion).