By Doug Palmer

WASHINGTON, April 14 (Reuters) - The Obama administration could label China as a currency manipulator when it takes its first official stab at the controversial issue in a report due on Wednesday, a top U.S. business official said.

"I expect them to label China a currency manipulator, with some ameliorative language to soften it a bit -- which won't make the Chinese any less irritated," said Bill Reinsch, president of the National Foreign Trade Council, which represents major exporters such as Boeing (BA.N: Quote, Profile, Research).

Reinsch, however, also said he expected the highly sensitive semi-annual U.S. Treasury Department report would be delayed, as routinely occurred during the administration of former President George W. Bush.

Asked if the report would be released on Wednesday, Treasury Department spokeswoman Heather Wong said she could only say the report would come "soon."

The National Association of Manufacturers, the AFL-CIO labor federation and many other groups pressed the Bush administration for years to formally label China a currency manipulator in a semi-annual report on the exchange rate practices of major U.S. trading partners.

They accuse China of artificially depressing the value of its yuan currency CNY= CNY=CFXS to give its companies an unfair trade advantage.

President Barack Obama picked up that rhetoric during his election campaign last year.

Obama told the National Council of Textile Organizations in a letter just two weeks before his election "that the massive current account surpluses accumulated by China are directly related to its manipulation of its currency's value."