The department's latest Semi-Annual Report to the Congress on International Economic and Exchange Rate Policies highlighted the need for greater exchange rate flexibility, most notably by China, but also in other major economies, the department reported on its Web site.
The report covers international economic and foreign exchange developments in the first half of 2011.
Citing numerous instances, the Treasury report said the standards under the statutes for making the manipulator designation "have not been met with respect to China."
"Nonetheless, the movement of the (yuan) to date is insufficient," the report said. "Treasury will closely monitor the pace of (yuan) appreciation and press for policy changes that yield greater exchange rate flexibility, a level playing field, and a sustained shift to domestic demand-led growth."
China has been accused of artificially keeping its currency undervalued, giving its exports an unfair trade advantage and running up trade surpluses against its trading partners.
The United States has been pressing China to speed up the appreciation of its currency, saying the current appreciation is too slow.
A Senate-passed bill that has yet to become law calls for the U.S. government to impose punitive tariffs on Chinese imports if the current imbalance continues. China has rejected U.S. criticism, saying international balance of payments and currency markets show the value (yuan) is getting to a reasonable and balanced level.