(Adds OneWest comment)
NEW YORK, April 8 (Reuters) - A lawsuit has been unsealed accusing OneWest Bank FSB, a lender once known as IndyMac Bancorp Inc, of causing the U.S. government to improperly pay out $206 million under a federal program to help struggling homeowners avoid foreclosure.
According to a so-called whistleblower complaint made public on Tuesday, OneWest violated the 2009 Home Affordable Modification Program (HAMP) by routinely tacking on thousands of dollars of debt to borrowers' principal balances, without providing required disclosures of terms such as payment amounts, interest rates, finance charges and late payment policies.
The complaint said OneWest would "virtually always" loan new amounts of principal, averaging $17,000 per contract, and fail to itemize as required under the federal Truth in Lending Act, making it impossible to tell whether the sums were proper.
As a result, the lawsuit says the government paid $206 million of incentives under HAMP to help homeowners avoid foreclosure because of OneWest's false statements, including $58.3 million to OneWest.
The complaint was unsealed after the U.S. Department of Justice declined to intervene in the case.
It was filed on behalf of Michael Fisher, who according to the complaint worked on modifications for OneWest and other servicers at California and Texas law firms from 2008 until 2012. His lawsuit seeks triple damages under the False Claims Act, which lets individuals sue government contractors for allegedly defrauding taxpayers.
"We look forward to rebutting these groundless claims in court," a OneWest spokesman said. He added that "numerous" government agencies regularly audit the bank's loan modification activities, and have never identified material errors.
OneWest was created in March 2009 by investors including Paulson & Co and JC Flowers & Co, and bought many assets of IndyMac, a mortgage lender that had failed the previous July.
Based in Pasadena, California, OneWest now has more than $24 billion of assets and 75 branches, according to its website.
Samuel Boyd, a Dallas-based lawyer for Fisher, did not immediately respond to a request for comment.
HAMP was part of the Obama administration's effort to address the U.S. housing crisis. Through January, more than 1.3 million borrowers had received permanent loan modifications, according to the Treasury Department, less than half the original goal of 3 million to 4 million.
The case is U.S. ex rel Fisher v. OneWest Bank FSB, U.S. District Court, Southern District of New York, No. 12-09352.
(Reporting by Jonathan Stempel in New York; Editing by David Gregorio and Lisa Shumaker)