Treasury Secretary Timothy Geithner said on Wednesday the International Monetary Fund was in a position to raise a substantial amount of capital quickly but that it cannot substitute for a forceful response by Europe to its debt crisis.

"The IMF isa  in a very good position ... to demonstrate to the world that ... it has the ability to raise additional finance from other countries very, very quickly if it needs to do that," Geithner said at the Brookings Institution.

"I think that's good because that will prove to the world that there's a substantial capacity that can reinforce what Europeans are doing and help cushion, if necessary, the effects of any European trauma on the rest of the world."

"What we did not want to see is people look to the IMF as a way to substitute for a more forceful European response," he said.

Raising more cash for the IMF to build a bigger firewall against potential spillover of Europe's crisis is expected to be a key topic at weekend semi-annual meetings of the IMF and World Bank.

Some countries have already said they are willing to do so but the United States has said repeatedly that it is not prepared to go to Congress to seek more money for the IMF.

Geithner said the United States supports IMF efforts to help Europe make needed reforms and said any view that the United States was holding back from helping Europe was incorrect.