Soros, worth about $7 billion, has already donated several million dollars to grass-roots groups campaigning against Bush.

"I am ready to put my money where my mouth is," the Hungarian-born American billionaire said on Monday at the Carnegie Endowment for International Peace.

"I have made rejection of the Bush doctrine the central project of my life for the next year," he said.

"Its got a rise out of me and it will probably find an expression in the amount I donate," Soros said.

Bankroll

Soros gave $10 million to America Coming Together, which campaigns to increase the number of people taking part in elections. He donated another $2.5million to Moveon.org, an internet campaign group that opposed the war in Iraq.

Soros' criticism has earned him the Bush administration's scorn, but the billionaire is staying firm in his opposition to the US President.

"2004 is not an ordinary election. It is a referendum on the Bush doctrine," he said.

"The misinterpretation is that might is right and that we ought to use our dominant position to impose our will on the world," Soros said.

"We can either deflate the bubble before it does any more damage or we can endorse the Bush doctrine and suffer the consequences," Soros argued.