The United States on Monday reiterated its call for China's currency to be market-based, as lawmakers warned they would act if there was no movement from China on revaluing the yuan.

China's policy of intervening in currency markets to keep the yuan from rising to boost exports has drawn the ire of American politicians, who face elections in November at a time when the U.S. unemployment rate is stubbornly stuck at nearly 10 percent.

The president has spoken repeatedly and recently that China's currency must be market-based, White House spokesman Robert Gibbs told reporters.

With China on holiday, there was no official response from Beijing to a weekend announcement that Treasury Secretary Timothy Geithner would postpone a report due out on April 15 that could have branded China a currency manipulator.

A Chinese government economist said the U.S. decision to delay the contentious report created some room for further consultations and negotiations.

But I don't think there will be a yuan adjustment in the near-term. We need to see whether China's export recovery will be sustained and need to see whether companies can cope with a stronger yuan, said Huo Jianguo, head of the Commerce Ministry's think-thank.

A U.S. Senate Finance Committee aide said Committee Chairman Max Baucus was worried that delaying the currency decision repeats the same failed approach to U.S.-China economic policy.

He will be watching China's actions closely in the coming weeks and months to determine what legislative steps need to be taken to ensure that China's currency practice does not harm America's ranchers, farmers and workers, the aide said.

American Iron and Steel Institute President and CEO Thomas Gibson voiced disappointment and accused Geithner of side-stepping his obligation under U.S. law.

We cannot continue to give China and other governments a pass on this critical issue, he said in a statement.

G20 AND BILATERAL TALKS

The U.S. decision to delay the currency report followed Thursday's announcement that Chinese President Hu Jintao will attend a nuclear security meeting in Washington April 12-13.

The United States has sought Chinese diplomatic help in curbing nuclear proliferation in Iran and North Korea. Both Washington and Beijing have tried to keep bilateral tensions in check after U.S. arms sales to Taiwan and a dispute with Google over Internet freedoms made for a rocky start to 2010.

Declaring China a currency manipulator, which the Obama administration declined to do in the 2009 reports, would require Washington to enter into consultations with Beijing through the International Monetary Fund.

Geithner said he would use meetings of the Group of 20 and a U.S.-China strategic dialogue in Beijing in May to urge China to budge on the yuan. President Barack Obama, many U.S. lawmakers and several economists say the currency is kept artificially low to boost Chinese exports.

China's yuan barely reacted in offshore forward Asian markets on Monday, apparently reflecting investor sentiment that the U.S. decision will not shift of the value of the yuan a year hence.

One-year NDFs, units which traders use to bet on the future value of a currency, moved from 6.645 per dollar to 6.639, which still implied an appreciation of about 2.8 percent in a year's time. But markets in Hong Kong and Shanghai, the main centers for yuan trading, were closed for holidays.

Analysts have said Beijing, loathe to be seen as bending to foreign pressure, may feel freer to nudge up the yuan if Washington dims its spotlight on public demands.

CHINA BUYING SPREE

Scott Paul, head of the Alliance for American Manufacturing, said pressure will only grow for real results out of the bilateral and multilateral discussions with China and that threats of action were necessary.

History shows us that China understands consequences better than it responds to quiet diplomacy, he said in a statement calling on the U.S. Congress to take action.

The Baucus aide's remarks followed warnings by other U.S. lawmakers who are crafting legislation that would apply duties on Chinese goods to offset the price advantage they say China's exporters gain by selling in an artificially cheap currency.

A pause in public carping about the yuan makes a lot of sense to calm things down a little before anger gets out of hand, but this will only be productive if there is a frank and open discussion about the problems facing the two countries, said finance professor Michael Pettis of Peking University.

But Pettis, also a fellow at the Carnegie Endowment for International Peace, said such talks will need to involve other big trade surplus countries like Japan and Germany and might not bring results as quickly as U.S. politicians expect.

High unemployment in the U.S. will cause the currency issue to resurface very quickly. And without real progress on correcting the imbalances, and quickly, which I think is likely to be difficult, the anger will persist, he said.

Several Chinese economists quoted in the overseas edition of the People's Daily, the official newspaper of China's ruling Communist Party, maintained that the yuan was not to blame for the U.S. trade deficit.

But Li Daokui, a member of the central bank's monetary policy committee, said China could nonetheless buy more U.S. goods to ease pressure from the White House and Congress.

China can increase purchases from (U.S.) states facing mass unemployment because of recession in the manufacturing sector, said Li, a Harvard-trained economist at Tsinghua University in Beijing.

Beijing let the yuan rise 21 percent against the U.S. dollar between July 2005 and July 2008 before effectively repegging the currency, also called the renminbi, near 6.83 to the dollar to help the economy through the 2008-2009 financial crisis.

The United States' deficit in trade with China fell to $227 billion in 2009 from a record $268 billion in 2008, largely the result of the global recession, but the Obama administration is keen to lift exports and employment.

(Additional reporting by Patricia Zengerle, Doug Palmer, Matt Spetalnick in Washington and Kevin Yao Buckley in Beijing, editing by Philip Barbara)