"In 2009, the budget will have a deficit of 1.5 to 2 trillion rubles, which we will have to make up from the national Reserve Fund," Kudrin said on the Vesti TV channel.
"2009 will be the most difficult for the Russian and world economies. I cannot remember a worse year since the end of the Second World War," he said. "This will be the worst year for the economy in modern times."
Kudrin earlier said he could not rule out a 1 billion-ruble deficit next year.
In the 2009 budget approved by parliament, revenue exceeded expenditure by 1.9 billion rubles, but that document assumed an average oil price of $95 a barrel.
Kremlin aide Arkady Dvorkovich said Thursday that the budget deficit could exceed 5% of GDP in 2009 if the economy does not begin to recover by the middle of the year.
"If the situation follows a negative scenario and the economic recession lasts throughout next year, the deficit could exceed 5%," he said.