WASHINGTON (Reuters) - The U.S. Senate approved Nathan Sheets as the Treasury's top official on international affairs, charged with pressing Washington's position on everything from the value of China's currency to how to resolve Europe's debt crisis.

In a voice vote on Thursday, senators confirmed Sheets as Treasury's undersecretary for international affairs. President Barack Obama had nominated him in February.

Sheets will play a key role in U.S. financial diplomacy and told lawmakers in June he would continue to press Washington's view that China should let market forces determine the value of its currency. The Treasury and U.S. manufacturers say China's currency is undervalued, giving its exports an advantage in global markets.

Sheets had been working as a counselor to U.S. Treasury Secretary Jack Lew since February. Prior to that, he was the global head of international economics at Citigroup in New York, a position he held since 2011.

Sheets spent much of his earlier career as an economist at the Federal Reserve and had advised former Fed Chairman Ben Bernanke on international economics.

The Treasury post was previously occupied by Lael Brainard, who stepped down last year and was nominated and confirmed to the Fed's board of governors.

(Reporting by Rick Cowan; Writing by Jason Lange; Editing by Ken Wills)