By Jonathan Stempel and Joseph Ax

NEW YORK (Reuters) - A federal appeals court on Wednesday rejected an effort by news media to force prosecutors in the George Washington Bridge lane-closing scandal known as "Bridgegate" to disclose the names of unindicted co-conspirators.

Reversing a lower court ruling, the 3rd U.S. Circuit Court of Appeals in Philadelphia found no right of public access under the U.S. Constitution's First Amendment or the common law to a list of people implicated but not criminally charged.

The 3-0 decision came one day before jury selection was scheduled to begin in the trial of two former allies of New Jersey Governor Chris Christie who are accused of arranging the September 2013 shutdown of bridge access lanes in Fort Lee, New Jersey, causing several days of gridlock.

"Public access to judicial documents and court proceedings is a respected tradition and important legal principle, but it has bounds," Circuit Judge Kent Jordan wrote.

While it may make sense to release the names at trial, "that time is not here yet," he added.

Prosecutors accused William Baroni, a former deputy executive director of the Port Authority of New York and New Jersey, and Bridget Anne Kelly, a former Christie deputy chief of staff, of closing lanes to punish Fort Lee's Democratic mayor, Mark Sokolich, for not endorsing the successful re-election of Christie, a Republican.

Disclosing the list could have shown whether other Christie allies sought political payback by snarling traffic.

Another former Port Authority official, David Wildstein, is cooperating with prosecutors after pleading guilty.

Christie has denied involvement, but the scandal helped erode his once-high approval ratings. He ran unsuccessfully this year for the White House. His office had no immediate comment.

U.S. District Judge Susan Wigenton in Newark had in May ordered disclosing the names of unindicted co-conspirators, but a "John Doe" on the list appealed, fearing reputational harm.

Bruce Rosen, a lawyer for media companies including ABC, the Associated Press and the New York Times, in an email said his clients are disappointed, and no decision on an appeal has been made.

Doe's lawyer, Jenny Kramer, in an email said she was gratified that the appeals court "prevented disclosure of highly prejudicial material."

A spokesman for U.S. Attorney Paul Fishman in New Jersey, who supported Doe, declined to comment.

Baroni and Kelly have pleaded not guilty to wire fraud, civil rights deprivation and conspiracy charges, and received the list of names to help prepare for trial. Their lawyers did not immediately respond to requests for comment.

(Reporting by Joseph Ax and Jonathan Stempel; Editing by Chizu Nomiyama and Matthew Lewis)