China yesterday expressed concern at the decline in the dollar, joining a growing chorus of global policymakers alarmed by the weakness in the world's main reserve currency.

Premier Wen Jiabao told a business audience in Singapore it was becoming very difficult to manage China's $1,430bn foreign exchange reserves, saying that their value was under unprecedented pressure.

“We have never been experiencing such big pressure,” Mr Wen said, according to Reuters. “We are worried about how to preserve the value of our reserves.”

China keeps the currency composition of its reserves a state secret, but some analysts believe that more than two-thirds are probably still held in dollars.

Mr Wen's comments came as top international economic officials spoke out in support of a strong dollar in the aftermath of the weekend's Group of 20 summit in South Africa and Opec meeting in Riyadh.

Hank Paulson, the US Treasury Secretary, told reporters in Ghana, “a strong dollar is in our nation's interest”. He said the US economy had its “ups and downs” but said he believed that “our long-term economic strength will be reflected in currency markets.”

Mr Paulson and other top US officials, including President George W. Bush, have become increasingly vocal on the dollar in recent days in an apparent effort to signal that they are not indifferent to its fate.

Zhou Xiaochuan, China's central bank chief, said Beijing wanted a strong dollar because it would help to ensure an orderly resolution of the recent market instability caused by US mortgage lending problems.

“So in this sense, actually we hope to see a strong dollar,” Reuters quoted Mr Zhou as saying. “We support a strong dollar.”