WASHINGTON — Advocates of a bill promoting openness in government are fuming that a Republican senator is blocking a vote on the measure.

Dozens of journalism and advocacy groups supporting the Open Government Act say it would speed up the government's response to public requests for information under the federal Freedom of Information Act.

But Sen. Jon Kyl, R-Ariz., says the Justice Department has "uncharacteristically strong" objections to the bill. In a statement yesterday, he said he would block a vote until both sides could work out their differences.

Supporters of the bill are irate.

"This is a good-government bill that Democrats and Republicans alike can and should work together to enact. It should be passed without further delay," said Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., who sponsored the bill with Sen. John Cornyn, R-Texas.

Frustrated, Leahy now is pressing senators to clear the bill for a vote.

Advocates ranging from the Society of Professional Journalists to the Humane Society of the United States are particularly irked because Kyl initially objected under a Senate rule that allows one member with concerns to hold up legislation anonymously.

Kyl revealed his identity yesterday, days after the bill's backers launched an e-mail and telephone campaign, urging supporters to help in "smoking out 'Senator Secrecy.'" They pointed out the irony that an open-government bill was being blocked by someone using a rule that allowed secrecy.

Supporters say the bill would plug loopholes in the FOIA law by, among other things, clarifying when federal agencies would have to pay attorneys fees if they miss deadlines to provide information, and bolstering deadlines for the government's response to requests under the law.

Although the Justice Department has objected strenuously to several provisions, advocates say they have answered or addressed the major concerns.

For example, a section has been eliminated that would have lifted exemptions letting the government deny access to privileged or law-enforcement sensitive information, said Leahy spokeswoman Tracy Schmaler.

Kyl also has argued that forcing the government to pay attorneys fees — even when it settles a case without going to court — could make government agencies less likely to settle or change decisions about a FOIA request.

Advocates disagree. They say the government likely would pay less if it voluntarily disclosed records in court proceedings, giving it an incentive to release information earlier in the process.

Kyl said he raised concerns when the Judiciary Committee voted on the bill in April, and that Leahy agreed to work with him and the Justice Department to try to reach a consensus. But Leahy hasn't heard from Kyl on the bill since it passed the Judiciary Committee, Schmaler said.

A similar bill passed the House earlier this year. Advocates believe the Senate will approve it as well.

"This is an important, bipartisan issue that deserves the consideration of the full Senate," Cornyn said.