"Pegging the yuan to the dollar appears to be part of a deliberate strategy to support Chinese industry and boost exports," William Primosch, director of international business policy at the National Association of Manufacturers, told a congressional panel.

Manufacturers and high-technology representatives implored Congress and the Bush administration to push Beijing to adopt a market-based exchange rate regime rather than pegging the yuan to the dollar.

US manufacturers argue the yuan, which has been pegged at about 8.3 to the dollar over the past nine years, is undervalued by 15 per cent and is unfairly eating away at US exports.

The White House appears to be paying attention.

Treasury Secretary John Snow pressed the currency issue with Chinese leaders on a recent visit to Asia and the United States has used its position in the Group of Seven industrial powers to take up China's currency.

Bush is worried about the impact China's currency is having on US exporters, their jobs and votes as he casts his eye to next year's presidential election.

China is the fastest growing market for US goods, and some of the nation's biggest companies are scrambling for a slice of the action.

In September alone General Electric, Du Pont and Citigroup all announced investments and deals in China representing billions of dollars while Goldman Sachs is reportedly in talks to buy a 10-per cent stake in China Pacific Life Insurance.

Despite the mounting appeals, administration officials insisted they are doing all they can to take the argument to Beijing.

"We are making progress, it's limited. We understand the frustrations of our manufacturers," Charles Freeman, deputy assistant US trade representative, who handles China, told the panel.

He said Washington "wants to encourage China to play by the rules," but added "it is extremely tough going negotiating with the Chinese."

Industry's increasing impatience on the currency issue comes ahead of a high-level visit by US Commerce Secretary Don Evans to China next month. Chinese Premier Wen Jiabao will visit the United States in December.

The manufacturers group is the most vocal of those pressing the White House on the currency matter, but other industries, including high-technology and services, appear to be now stepping into line.