President Reagan denounced the congressional Iran-contra hearings yesterday as filled with "hearsay" and said "there ain't no smoking gun" that would show he was aware of the diversion of money to the Nicaraguan contras from arms sales to Iran.

Reagan's comments represented one of the few times he has spoken out forcefully against the Iran-contra inquiry. He initially had encouraged and promised to cooperate with the investigation, but has increasingly challenged testimony and statements by members as the hearings focused on whether the White House breached the law in aiding the rebels fighting the government of Nicaragua.

At a session with economics reporters from cities outside Washington yesterday, Reagan was asked whether he was trying to emphasize budget reform issues to "get the spotlight off the Iran-contra hearings here in Washington." He replied:

"I think that spotlight has been growing so dim in recent days, that when you get a mile and a half away from the Potomac River, there are an awful lot of people that have gone back to their favorite television shows. And I don't blame them.

"I've never heard so much hearsay in all my life that wouldn't be permitted in a courtroom for a minute and a half, and it's taken as gospel by those who want to go further with this," he said.

"But I shouldn't get lost in that. No," he said, turning to the subject of revising the budget process.

A Washington Post-ABC News Poll two weeks ago found that most Americans are not paying close attention to the televised hearings, which resume next Tuesday. Fifty-four percent of those questioned said they were "not closely" following the hearings and 39 percent said "somewhat closely"; only 7 percent said "very closely."

Questioned yesterday about charges from Democratic presidential candidates that his administration has lacked integrity, Reagan accused the Democrats of "pure demagoguery."

"I don't think there's anyone that's ever been in this job -- ever -- that has not gone to bed every night knowing that with the thousands of people that are out there, there could be somebody that's breaking the rules someplace, and you try to get at that and do something about it," he said. Reagan said he would "challenge" the claim that the administration has lacked integrity, and "I have tried to keep every promise that I made, and have kept a lot of them."

The president then launched into a restatement of economic statistics on the performance of his administration.

When a reporter reminded him that more than 100 members of the administration have left "under some sort of cloud or scandal," Reagan responded by recalling a statement from former labor secretary Raymond J. Donovan after his recent acquittal on fraud charges.

"Yes, I remember when Ray Donovan left, and I remember his sizable plea the other day -- now, how does he get back his reputation," Reagan said.

"A number of people in our administration -- there have been things that have been uncovered by someone, let's say, that -- in the past, before they ever came here. But isn't it the very fact that we are uncovering if there's something going wrong and something being done about it. We're not covering it up or hiding it."

Reagan's comment denying the existence of a "smoking gun" was made as he was walking into a meeting with Senate Republican leaders on Capitol Hill. He was responding to questions that have been raised by congressional investigators about an undated memo describing the diversion of Iran arms profits to the contras.

Speaking hypothetically, Rep. Lee H. Hamilton (D-Ind.), chairman of the House select investigating panel, said last weekend that if Reagan had received the memo it would be grounds to begin impeachment proceedings. The president has denied ever receiving the memo, which was prepared by Lt. Col. Oliver L. North, the fired National Security Council aide, and sent to the national security adviser at the time, Vice Adm. John M. Poindexter.

"I have said repeatedly that I never saw any such memorandum," Reagan said yesterday as he left the Senate meeting.

Chief of staff Howard H. Baker Jr. said Reagan "did not receive that memo. The president did not know of that memo and I believe he will tell you that. And I don't believe they'll be any evidence to the contrary because there is no evidence to the contrary."

Baker, like Reagan, denied that Reagan's latest emphasis on budget process issues was an attempt to divert attention from the Iran-contra hearings. "The president's doing what a president should do," Baker said, adding that Reagan was addressing important public issues.

"That's very presidential. That certainly is not meant to relieve him of the distresses of the Iran-contra hearings."