China is doing its best to move toward a freely traded currency, a central bank official said, appealing for understanding from two US senators who are threatening trade sanctions unless the yuan's value rises.

"They should understand that China is doing its best,'' Wu Xiaoling, vice governor of the People's Bank of China, told reporters in Beijing Saturday ahead of next week's visit by senators Lindsey Graham and Charles Schumer. ''China's economic restructuring needs a process.''

Graham, a Republican from South Carolina, and Schumer, a Democrat from New York, are sponsoring legislation that would impose tariffs on Chinese imports unless the yuan is allowed to strengthen. The senators will meet Chinese officials in Beijing and Shanghai before deciding whether to proceed with a vote on their bill by March 31.

The yuan this week had its biggest weekly gain against the dollar since the government scrapped a decade-old peg in July, after Premier Wen Jiabao promised more flexibility. China is under pressure to let the yuan trade more freely before the U.S. Treasury's semiannual report on global currency manipulation and President Hu Jintao's visit to the U.S. next month.

The yuan's "flexibility is increasing gradually,'' Wu said in a speech to a banking conference today. The central bank will improve the exchange-rate mechanism "actively and progressively'' and "allow market supply and demand to play a fundamental role in forming the exchange rate.''

Wen's Pledge

U.S. lawmakers and manufacturers accuse China of keeping the yuan's value artificially low to spur exports. China's trade surplus tripled to a record $102 billion last year, helping to drive economic growth of 9.9 percent, the fastest among the world's major economies.

'A flexible exchange rate will help to improve the international balance of payments, but large-scale fluctuations will harm the stable development of the economy,'' Wu said. She said the central bank isn't concerned about U.S. pressure for faster progress toward a freely traded currency.

China on July 21 reset the yuan's value at 8.11 to the dollar, a 2.1 percent appreciation from the pegged level where it had been held since 1995, and linked its value to a basket of currencies including the euro and yen. Under the system, the yuan is allowed to rise or fall 0.3 percent against the dollar either side of a daily rate announced by the central bank.

Trading Band

The yuan, a denomination of China's currency, the renminbi, rose 0.1 percent to 8.0313 against the dollar at 3:30 p.m. in Shanghai Friday, bringing its gain for the week to 0.2 percent, according to data compiled by Bloomberg. It has gained almost 1 percent since the revaluation.

The yuan's daily fluctuation exceeded 0.1 percent for the first time on March 15, a day after Premier Wen said China will "add more flexibility to the exchange rate's trading band.''

Wu said the central bank is studying introducing interest- rate futures and more foreign-exchange derivatives to give companies and financial institutions tools to hedge against a more volatile exchange rate.

The central bank will also "release reasonable demand'' in the foreign exchange market while "controlling abnormal foreign- exchange supply,'' she said.

Treasury Review

China allowed the yuan to be freely convertible under the current account in December 1996, removing limits on the use of foreign exchange for trade in goods and services. Restrictions on inflows and outflows of money for investment purposes, or the capital account, mean the currency market is dominated by companies involved in trade.

China's foreign-exchange reserves jumped a third to $818.9 billion last year, the world's second-largest after those of Japan, driven by exports and foreign direct investment.

U.S. Treasury Secretary John Snow is under pressure from Congress to brand China a manipulator of exchange rates, a step the U.S. hasn't taken since 1994. Treasury officials sounded out investors about the potential impact of such a finding, people familiar with the situation said on Feb. 15. The Treasury's review is due on April 15.

China isn't manipulating the yuan and trade with the U.S. benefits both nations, Ma Kai, chairman of the National Development and Reform Commission, the nation's top economic planning agency, said in Beijing Friday.

Goods manufactured in China help U.S. consumers save $100 billion a year, while U.S. companies last year hired 50,000 new workers to help import goods from China, he said.

China won't bow to pressure from the U.S. to bring forward its timetable for yuan flexibility, central bank Governor Zhou Xiaochuan told reporters in Beijing on March 11. China will follow its "own principles" on yuan reform and current fluctuations in the exchange rate are appropriate, he said.