The Senate Judiciary Committee and the Justice Department are heading toward a confrontation over congressional access to closed investigative files on public corruption cases that weren't prosecuted.

Sen. Dennis DeConcini (D-Ariz.) threatened yesterday to subpoena 15 of the files unless the department agrees to turn over the material by Friday. He said he believed Justice "is hiding behind the doctine of 'prosecutorial discretion' to avoid review and oversight" of the criminal division's public integrity section.

The senator said the department "is holding the American people in contempt" by withholding the documents. He also complained that the department had already turned over some of the same files to the Senate Governmental Affairs Committee.

DeConcini then adjourned the hearing without giving Philip B. Heymann, head of the criminal division, a chance to respond. So Heymann sat on the witness table and told reporters that the department needed additional safeguards for the confidentiality of the material before complying with the committee demand.

The public integrity section was formed in 1976 to monitor public corruption cases, including those in Congress. The Judiciary Committee is now, in effect, asking, "Who will watch the watchdog?" though its interest was spurred initially by a controversy over the nomination of the section chief, Thomas H. Henderson, to be special counsel to the Merit Systems Protection Board.

Heymann said he was dismayed at allegations that the department may have manipulated cases to protect White House aides or other, high government officials. "As to political untouchability, I'm willing to stand on our record of the hell we have given the White House and Congress," he said.

He referred to the unsuccessful indictments of presidential condifants Bert Lance and Smith Bagley, the appointment of special prosecutors to investigate Hamilton Jordan and the Carter family warehouse, and the Abscam investigations of members of Congress, he said.

By comparison, he said he'd never heard of most of the cases the committee asked for. He said there appeared to be a "lot of personal stakes" in picking the cases.

For instance, several of the cases were brought to the committee's attention by a Pittsburgh man, John Nard, who has been complaining about his treatment by Justice for years. Nard also once was represented by Sen. Orrin Hatch (R-Utah), a member of the committee.

Other cases were added to the list, committee sources acknowledged, because individual investigators had been interested in them while working for other committees on the House side.

The public integrity section's handling of other publicized cases -- such as the investigation of allegations of South Korean bribery in Congress, possible perjury by International Telephone and Telegraph Corp. executive Harold Geneen, or Sen. Herman Talmadge -- were not included in the committee list.

Heymann told reporters he was concerned that unlimited access to department files could lead to damage to the reputations of persons who were never prosecuted.

"The possibility of abuse of power is too recently known," Heymann said, in an apparent reference to the Nixon White House's access to Watergate investigative files.

Heymann said he hoped the committee would consider the Justice Department's request for additional safeguards. DeConcini said in a phone call after the hearing that he was "willing to talk" further with the department, but was still planning to ask for a committee subpoena Tuesday.

Paticipants from both sides admit privately that a breakdown in communications over two valid and competing matters -- congressional oversight and Justice's privacy concerns -- has escalated until things may be beyond the control of either party.