A band of House Democrats is fuming at Treasury Secretary Timothy Geithner for delaying a biannual report to Congress on international exchange rate policies, charging Geithner is trying to avoid addressing the thorny issue of Chinese currency manipulation.

Members of the House Populist Caucus, led by Rep. Bruce Braley (D-Iowa), said Wednesday that Geithner’s decision to postpone the statutory April 15 release of the report is “completely unacceptable and needs immediate corrective action” since China has been undervaluing its currency for years.

“In this time of economic difficulty, we must do everything we can to promote and protect U.S. jobs and workers,” Braley and 11 other Members said in a statement. “The Obama Administration must identify China as a currency manipulator and use all available authority and resources to end this unfair trade practice without delay.”

China would face a round of consultation and possible sanctions if the administration were to label it a currency manipulator.

Geithner, who arrived in China on Thursday, announced last weekend that he planned to delay the report, citing the need for high-level talks with China as the best way to proceed on the matter. The White House is also hosting Chinese Premier Wen Jiabao later this month.

A Braley spokeswoman said she did not know if the lawmakers had spoken directly with Geithner about their concerns. A Treasury spokeswoman had no comment.