WASHINGTON (Reuters) - The judge overseeing the Justice Department's bid to stop AT&T (>> AT&T) from buying Time Warner (>> Time Warner) said Thursday that he would deny a request to tighten protections on confidential data.

Walt Disney Co (>> Walt Disney Company (The)) and Twenty-First Century Fox Inc (>> Twenty-First Century Fox) had requested that a protective order on sensitive information be strengthened for fear that their data would be inadvertently exposed in a trial next year.

"I'm going to deny the order," said Judge Richard Leon of the U.S. District Court for the District of Columbia.

Disney and Fox have given data to the Justice Department, which is using it to build a case against AT&T's bid to buy Time Warner. The companies say they fear that executives with AT&T, which owns satellite TV provider DirecTV, could inadvertently gain access to it during the trial.

Leon had given access to confidential information to the court, Justice Department lawyers and staff, service providers and AT&T and Time Warner's outside counsel.

The Justice Department sued in November to stop AT&T, the No. 2 U.S. wireless company, from buying Time Warner for $85 billion because of concerns that it could raise prices for rivals and pay-TV subscribers and hamper the development of online video.

A trial to decide the matter is set to begin on March 19, and run about 15 days, according to a court filing.

(Reporting by Diane Bartz; Editing by Cynthia Osterman)

By Diane Bartz