A Russian court on Wednesday convicted four former local officials of negligence during floods last year that killed more than 170 people, sentencing three of them to serve time.

Flash flooding of a local mountain river in the southern town of Krymsk killed scores in their sleep in the pre-dawn hours on July 7, 2012 after officials issued no flood warning, in the worst such disaster of the post-Soviet era.

The Abinsk Regional Court sentenced the former head of Krymsk district Vasily Krutko to six years in a colony settlement -- a penitentiary facility where inmates have more freedom than in a penal colony but still observe strict curfews.

Former Krymsk mayor Vladimir Ulanovsky was sentenced to three-and-a-half years, while the local emergency situations official Viktor Zhdanov was sentenced to four-and-a-half years.

Irina Ryabchenko, former head of the neighbouring village of Nizhnebakanskaya, which was also affected, received a suspended sentence of three-and-a-half years, according to a statement from the Russian prosecutor general.

The officials "did not announce the emergency situation in time and did not warn and rescue people," the statement said.

After the tragedy, Krutko, Ulanovsky and Ryabchenko also ordered the creation of "official documents with false information about having issued a timely warning," the statement said. The three were also convicted of forgery.

The prosecutor's statement cited a death toll of 153 people, although regional authorities said at the time that 172 people had died in the flood.

Observers have called the catastrophe a failure not only on the part of local officials, but also the region's influential pro-Kremlin governor, Alexander Tkachev, and even President Vladimir Putin himself, accusing the authorities of a blatant disregard for human life.

Krymsk is located about 200 kilometres (120 miles) northwest of the Black Sea resort of Sochi, where Russia will host the 2014 Winter Olympic Games.

The conviction and sentencing come as Russia battles new, record-breaking floods in the Far East that have forced authorities to evacuate more than 23,000 people and raised fresh questions about the government's readiness to handle natural disasters.