Praising the entrepreneurial spirit of the American enterprise, Prime Minister Manmohan Singh has said that there can be no substitution for the US dollar.

"As far as I can see right now there is no substitute for the dollar," the prime minister said in an interview to CNN.

Responding to questions about the economic crisis in the United States, the prime minister said: "There is a temporary setback and temporary questioning, about relevance of the American model, but I have seen these things much before."

Singh said even the Chinese, who holds $2.5 trillion in reserve assets, have not disposed off even a fraction of them.

"That is a measure of the confidence that the world has in the dollar. There are problems. There is the confidence problem, which can be very destabilising," he said.

"My own feeling is that the world has not entered an era of irreversible shift in the economic strength of the United States," he added.