Grand jury proceedings, traditionally cloaked in absolute secrecy by government prosecutors, are not automatically protected from disclosure under the federal Freedom of Information Act, a U.S. District judge has ruled.

The Justice Department has routinely shielded grand jury information from release under the Act by relying on a federal court rule that holds such proceedings are secret, and prohibits disclosure except in rare circumstances.

Judge Aubrey E. Robinson Jr., in a brief three-page decision handed down Wednesday, said that the rule does not apply to the Freedom of Information Act and cannot be used to block a request for grand jury information. He ordered Justice to turn over documents that had been requested by a Washington shop owner.

Robinson acknowledged that application of the act to grand jury information "threatens the grand jury process." And he noted that the federal rule that the government depended on was intended to "preserve an important constitutional process" that "will be seriously endangered unless secrecy is ensured."

Nevertheless, Robinson said, only the Congress or higher courts can take action to amend current law to specifically protect grand jury proceedings from disclosure under the act.

The Justice Department is expected to ask Robinson either to reconsider his ruling or postpone its effect until the case can be taken to the U.S. Court of Appeals. Robinson's ruling is believed to represent the first time that a judge has rejected the disclosure exemption traditionally cited by the government and routinely upheld by other judges.

Government lawyers said yesterday that Robinson's decision would probably apply only to completed grand jury proceedings, since the Freedom of Information Act specifically exempts information from ongoing investigations from public disclosure.

The act also exempts from disclosure investigative techniques and procedures, information that would violate personal privacy of parties to a case and trade secrets, among other things.

In the case before Robinson, however, the government withheld grand jury transcripts, subpoenas and records of appearances of witnesses before the grand jury, notes about testimony of those witnesses and ballots and draft indictments that were before the grand jury. The case involved a wide ranging Freedom of Information request filed by James M. Piccolo, 37, the owner of Souvenir City at 934 7th St. NW.

Piccolo was convicted in 1979 in D.C. Superior Court of receiving stolen property and wanted the information in connection with his appeal of the case, now before the D.C. Court of Appeals, according to his lawyer, Robert J. Flynn Jr.

In denying Piccolo access to that information, the Justice Department relied solely on a broad exemption to the Freedom of Information Act that says the government can withhold information that is specifically protected from disclosure by a federal statute. The "statute" that the government has consistently relied on in connection with that exemption in a section of the Federal Rules of Criminal Procedure that states grand jury proceedings are to be kept secret.

Robinson, however, said that the rule cited by the government is not a "statute" because it was not a law enacted by Congress. The federal rules, which govern criminal proceedings in federal courts, are issued by the U.S. Supreme Court and reviewed by Congress, which has the power to amend or reject them.

In reaching that decision, Robinson said he relied on a 1979 decision by the federal appeals court here which said that a parallel set of rules for civil proceedings is not a statute. Robinson said he was thus compelled to reject the government's contention in Piccolo's case, adding that only the Congress or a higher court could change the situation.