"This proposal in the name of so-called currency misalignment is protectionism and a serious violation of World Trade Organization rules, and won't be able to resolve America's own economic and employment problems."

Ma Zhaoxu, a foreign ministry spokesman commenting after the US Senate passed a bill enabling US companies to seek duties for "misaligned currencies".

"Many believe the situation is even worse than the onset of the last global financial crisis."

Zhou Qiren, director of the National School of Development, Peking University, saying that profits of small businesses in the Pearl River Delta region have declined and companies are facing tough operating conditions.