WASHINGTON, March 13 (Reuters) - A congressional study released on Thursday found serious shortcomings in the way the U.S. Federal Communications Commission handles complaints from consumers.

A study by the Government Accountability Office concluded that about 83 percent of the complaint investigations conducted by the FCC between 2003 and 2006 were closed without any enforcement action taken by the agency, and that it was impossible to determine why because the FCC did not collect enough data to follow up.

"Without an effective FCC enforcement program, consumers are left out in the cold," Edward Markey, chairman of the House subcommittee on telecommunications and the Internet, said after the report was issued.

The FCC is responsible for looking into complaints about phone carriers, as well as alleged violations of do-not-call restrictions by telemarketers, and alleged violation of indecency rules by broadcasters.

According to the GAO, the FCC's enforcement bureau took enforcement action in 3,400 cases, or about 9 percent of the time. In another 32,200 cases, it said, the agency closed cases without taking action. In the remaining 3,200 cases, the GAO said, it was "not able to determine whether enforcement actions had been taken."

"Without key management tools, FCC may have difficulty fully assuring Congress and other stakeholders that it is meeting its enforcement mission of protecting the consumer, ensuring public safety, and encouraging competition," the GAO said..

FCC Chairman Kevin Martin responded to the GAO findings by saying, "I appreciate the GAO's examination of the FCC's enforcement efforts and welcome its recommendations."

However, the FCC disputed many of the GAO's conclusions. It said 71 percent of its investigations were closed after the agency determined there was no violation, while another 11 percent were closed because not enough information was provided by the people who filed those complaints.

The agency said it had already undertaken improvements to its complaint system that were suggested by the GAO. Martin said the agency has been responding to all consumer complaints since he became chairman in March 2005.

In its response, the FCC said the study contained a series of "incorrect statements" and was based on out-of-date information.

The FCC said it had assessed a record $43 million in fines last year and eliminated a backlog of more than 113,000 complaints in recent years. (Editing by Gary Hill)

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