Sept. 25 (Bloomberg) -- U.S. Justice Department officials need more information to determine whether the proposed merger of Sirius Satellite Radio Inc. and XM Satellite Radio Holdings Inc. would hurt consumers, the agency's antitrust chief told Congress.

Thomas O. Barnett, head of the department's antitrust division, declined to give lawmakers a timetable on when he would decide whether to approve the combination or challenge it in court.

``I can't give you an exact time frame,'' Barnett told Representative Ric Keller, a Florida Republican, at a hearing of the House Judiciary Committee's antitrust task force.

``We want to get the information that we need so that we can conduct an appropriate analysis and evaluation,'' Barnett said. ``We want to do it as quickly as possible, but we also want to get the right answer.''

The Federal Communications Commission is also reviewing the proposed combination, first announced in February, of the only two U.S. providers of satellite radio. FCC Chairman Kevin Martin said Sept. 11 that the commission will vote on the transaction in the fourth quarter.

To contact the reporter on this story: James Rowley in Washington at jarowley@bloomberg.net.

Last Updated: September 25, 2007 18:48 EDT