That will be harder if China sticks to its export-centric yuan policy.

ECONOMIST: America and the yuan: The truth hurts | The

Mr King concludes that the biggest problem for China's current exchange-rate policy is not the yuan itself but the performance of the dollar.

ECONOMIST: Economics focus

Beijing says it has allowed the yuan greater flexibility but argues its policy is driven by domestic concerns such as maintaining economic growth.

BBC: Yuan notes being exchanged

On Friday, Mr Snow told CNBC television that China had made "an important first step" by ending the policy of pegging the yuan to US dollar.

BBC: NEWS | Business | Snow to focus on US-China tension

Another reason for hesitation is that the theory that revaluing the yuan will allow Beijing to tighten its monetary policy is too simplistic.

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Some forecasters, such as the IMF, expect China's trade surplus to start widening again this year unless the government makes bold policy changes, such as revaluing the yuan.

ECONOMIST: China's export prospects

Despite these cautionary words, many U.S. lawmakers are not impressed by the 0.8 percent rise in the value of the yuan against the dollar since China adopted its new policy.

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Since announcing this new policy in 2005, the value of the yuan has appreciated by 33 percent against the dollar.

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China's monetary policy must also be guided by the need to maintain the yuan's peg to the dollar.

ECONOMIST: Other reasons to worry