The Communist Party expects that the global financial crisis will cause social unrest and help it challenge for power, the party's leader said on Saturday.

Gennady Zyuganov told the party's annual congress that the Communists should make maximum use of the growing public discontent caused by the economic downturn to try to restore their political strength.

"The wind of history is blowing in our sails again … At this time of crisis, the world of imperialism is starting to die. We are standing on the threshold of political and social shifts," Zyuganov said in a two-hour speech that opened the congress.

The Communists ruled the Soviet Union for eight decades and remained a major opposition force for several years after the collapse of the Soviet Union at the end of 1991.

But the party has since lost much of its authority, and many analysts say it is too weak to seriously challenge for power.

The Russian authorities are trying to minimize the impact of the financial crisis by promising billions of dollars of state aid. Prime Minister Vladimir Putin has pledged higher social payments to the needy and lower taxes for business.

"The authorities are clearly not coping with managing the country…A mass social protest is brewing, and it is hard to predict now when and in what shape it will explode," Zyuganov said.

The Kremlin has acknowledged that the crisis will lead to a rise in popular discontent, challenging the massive popularity that Putin secured in eight years as president and handed on to his successor, Dmitry Medvedev.

Medvedev has ordered police to stamp out any social unrest arising from the crisis, and Interior Minister Rashid Nurgaliyev has said higher unemployment could lead to a rise in crime.

"We should secure the support of society well before the political crisis comes…We have to squeeze everything we can from this situation," Zyuganov said.

Zyuganov trailed far behind Medvedev in the presidential election in March, and his party's contingent in parliament is dwarfed by the pro-Kremlin majority.

Many Russians associate Communist rule with empty shelves in the shops and endless queues.

Russia has been among the biggest losers in the global financial crisis. The benchmark RTS stock exchange has fallen about 70 percent since peaks in May, and the ruble has been hit by tumbling prices for oil, the country's main export.

The impact on ordinary people so far has been limited, partly because share ownership is not widespread and few people have private pensions. But firms in some sectors have started laying off staff.

The country's new liberal opposition movement, Solidarity, also predicts that the fallout from the economic crisis will force Putin and Medvedev from power by 2012.