WASHINGTON (Reuters) - President Barack Obama's administration is pressing Congress to restore an important weapon in the U.S. arsenal against subsidized imports from China by quickly passing legislation to undo a recent federal appellate court ruling.

"This matter is of the utmost urgency," U.S. Trade Representative Ron Kirk and Commerce Secretary John Bryson said in one of several letters they sent to members of Congress. It was dated January 18 and obtained by Reuters on Friday.

"Absent legislation, should the (court) decision become final, Commerce will be required to revoke all CVD orders and terminate all CVD proceedings involving non-market economies," the cabinet officials said.

That list includes "24 existing CVD orders on imports from China and Vietnam, as well as five pending investigations and two recently filed petitions," Bryson and Kirk said.

The ruling could require the Commerce Department to lift or deny duties on some $4.7 billion worth of subsidized imports, mostly from China, they said.

The December 19 court ruling originally was due to take effect shortly after Feb 2. However, the court this week gave the Commerce Department an extension until March 5.

On Wednesday, House of Representatives Ways and Means Committee Chairman Dave Camp said he was prepared to move quickly on a "narrowly targeted" bill to ensure the Commerce Department can impose countervailing duties on "non-market economies" like China and Vietnam.

(Reporting By Doug Palmer; Editing by Vicki Allen)