"The latest reports said 10 people were killed and 14 injured," Dmitry Kudryavtsev, head of the regional emergencies center's press service, said. "The number of people still being searched for is over 50. Reports on the 67 missing have not been confirmed."
Earlier reports said eight people were killed and 10 injured when two water ducts collapsed at 08:15 local time (00:15 GMT), flooding a turbine hall. The disaster is believed to have been triggered by the explosion of an oil transformer while workers were carrying out repairs.
However, the Sayano-Shushenskaya station's chief engineer Andrei Mitrofanov told the emergencies center on the telephone later that 72 people were still unaccounted for.
RusHydro, the owner of the Sayano-Shushenskaya station built in 1978, said it was facing 1.5 billion rubles ($46 million) in monthly losses due to the accident.
The accident has cut power supplies to homes and companies, including metal giants Evraz Group and RusAl, forcing them to switch to emergency power. Six factories in the nearby Altai region have reportedly shut down due to the electricity shortage.
The energy ministry has meanwhile said that power supplies disrupted in five Siberian regions, including at aluminum plants, had been restored using supplies from thermal power stations in Siberia and the European part of Russia.
"The situation is under the control of the ministry. All agencies have been engaged in ensuring uninterrupted supplies," minister Sergei Shmatko said. "It is premature to talk about what caused the accident. Not all the circumstances have been studied."
Shmatko said electricity prices could grow for consumers in the region.
"We believe prices could rise by 5-7% for consumers in Siberia," Shmatko said, adding the ministry's council for regulating national energy supplies would consider measures to prevent unjustified price hikes.
Under reforms of the electricity sector, 50% of electric power began to be sold at market prices as of July 1, 2009. Electricity prices for households are set by the state.
Analysts say power prices for industries could rise 20-30% in Siberia following the accident, which forced nearby thermal power stations to increase output to compensate for the Sayano-Shushenskaya station's closure.
RusHydro's acting chief, Vasily Zubakin, said earlier that generating units unaffected by the accident could be reactivated within 45 days, but that restoring the station completly could take up to four years.
Zubakin also said the plant's dam was not damaged in the accident and posed no threat to local residents.
He said more than 60 people were still unaccounted for, while four people earlier reported missing had been found - one, in a state of shock, in the station's underground facility, one retrieved from the water, and two others at their homes.
Zubakin said the search effort would continue through the night as more pumps and other equipment arrive at the scene.
Russian Emergency Situations Minister Sergei Shoigu is at the site, coordinating cleanup and search efforts.
President Dmitry Medvedev has expressed condolences to the victims' families.