Leaders of the Senate panel investigating the Iran-contra affair said they expect the panel's final report will not include a critical assessment of President Reagan's role.

Chairman Daniel K. Inouye (D-Hawaii) told a group of reporters, "We may say he might have been more prudent, but I don't think we will say he was guilty of malfeasance or nonfeasance."

Sen. Warren B. Rudman (R-N.H.), the committee vice chairman, said he felt Reagan's role was "largely a political question, and I'm not sure the committee has to judge how the president managed this event or that. We'll make some observations, but I don't expect the report to be highly critical because the facts speak for themselves."

Democratic members of the House Iran-contra panel said yesterday it is too early to speculate on what a final report may say about President Reagan. One senior Democrat observed that the panels will have trouble enough agreeing on one account of the facts of the affair, let alone find suitable language on more sensitive matters like the presidential role.

The two senators said during the midday break in yesterday's hearings that staff work on the report has begun, even though several key witnesses have yet to be heard. They predicted it will offer suggestions for improvements in National Security Council operations and -- perhaps -- endorse the creation of a single congressional committee to monitor intelligence agencies and covert operations.

But they knocked down the idea that the report would assess Reagan's responsibility for the affair or even go as far as the Tower commission did in criticizing what it called the president's "management style."

Their comments came as the congressional panels laid out a tentative schedule for the final round of witnesses. Former national security adviser John M. Poindexter is expected to conclude his testimony today and will be followed by James Radzimski, who was involved in maintaining sensitive NSC documents.

Former White House chief of staff Donald T. Regan will appear next, with Secretary of State George P. Shultz scheduled to follow. Next week, the panels will hear from Defense Secretary Caspar W. Weinberger and Attorney General Edwin Meese III.

Inouye said he thought it was "unfortunate {Reagan} will finish his term with a significant number of people questioning his veracity" and said it had weakened Reagan to the point that continued U.S. aid to the contras was unlikely to be approved by Congress this fall. Rudman called the Iran-contra affair "the only major blemish on his presidency" and said he still expected Reagan to achieve significant successes in the arms control and budget fields.

Inouye did not hesitate to say he thought it "outrageous" that Reagan let Poindexter resign and former NSC aide Lt. Col. Oliver L. North be fired last November without demanding a direct explanation from them of their actions.

Nonetheless, Inouye said the committee report will avoid such judgments because "whenever our president is weakened and our country divided, our adversary takes advantage."

He said he had hoped from the first "we never come across a smoking gun" linking Reagan to the diversion of funds, because "these are dangerous times to be going through that type of exercise {impeachment}."

Inouye said the committee probably will be unable to give a definitive factual version of what occurred in the arms sales and the financial transactions it has been investigating. "It is apparent at this stage," he said, "that when we file a final report, we'll have a lot of pieces missing from our puzzle. However, we will have enough pieces to present the American people a picture of what we think occurred."

He and Rudman said they hoped their panel and its House counterpart, which are holding joint hearings, will be able to agree on a statement of the facts of the case, but both conceded there are likely to be dissents and differences on policy recommendations.

They appear to have disagreements themselves. Inouye said he thought "the time may be coming" to scrap the separate House and Senate intelligence committees and create a single, small, joint committee -- a step several administration officials have urged as a way of reducing leaks.

Rudman said he favored such a proposal only if it allowed equal numbers of members from both parties and had a small membership and staff. "Merging the two committees as they are now would just pyramid the problem," he said.

Inouye also said one upshot of the affair is that congressional committees are likely to insist that Cabinet officials and other administration witnesses take an oath to tell the truth in their testimony. Rudman said that would have "a very chilling effect" on executive-congressional relations and was "no way to encourage good-faith dealings."