The Senate's senior intelligence overseer mystified his colleagues at a White House leadership breakfast Tuesday morning with a cryptic statement leaving the strong impression that members of the Senate Intelligence Committee are being spied upon.

Sen. Daniel K. Inouye (D-Hawaii), according to at least five persons who were present, appeared to hint to President Carter and the House-Senate leaders that members of the Intelligence Committee had been placed under surveillance, but he did not say who ordered it or who was conducting it.

One member who was present said Inouye's remarks implied that the purpose of the surveillance was to determine whether committee members were the source of leaks to the press on Central Intelligence Agency payments to foreign rulers.

However, both President Carter and the Intelligence Committee, in statements to The Washington Post, denied that members of the committee or staffers have been placed under FBI or CIA surveillance.

Presidential press secretary Jody Powell quoted the President as saying that he didn't think Inouye had said "anything so ridiculous." Powell pointed out that Inouye lacks authority to order surveillance of anyone, and said President Carter hasn't doen it.

Powell also added that Vice President Mondale had checked with the FBI and the CIA and both had said nothing of the sort is going on or will go on. But if they turn up something in their normal work indicating that a foreign intelligence agent is "targeting" a committee member or staffer, they will notify that person.

The Senate Intelligence Committee, and later Inouye himself, issued a flat denial that Inouye had ever asked that members or staff of the committee be placed under surveillance by U.S. intelligence agencies.

"I have never made such a request," Inouye said, "and no one has been placed under surveillance." He said his comments earlier at the White House had been misinterpreted.

Inouye said what he had requested was that the U.S. intelligence community "keep its eyes and ears open and learn of activities indicating we are being targeted" by foreign intelligence agents. "According to the FBI, there has been no attempt to infilitrate this committee," he added.

Sen. Gary Hart (D-Colo.), a member of the Intelligence Committee, said he understood Inouye to have meant that he wanted to be sure there was no foreign intelligence penetration of the Senate body. "As I understand it he meant we should have a counterintelligence defensive surveillance capability," explained Hart.

The Colorado Democrat said he was unaware of any breach of committee security by foreign agencies or any other reason for Inouye's announcement. The leadership meeting at which Inouye made the remark occurred four days after news reports of CIA payments to King Hussein of Jordan. Carter is understood to have been critical during the meeting of the news leaks on Hussein and subsidies to other foreign leaders.

Another source close to the committee said all Inouye had meant was that whhen a foreign agent who is being watched by U.S. security people happens to talke to a senator or staffer on the Intelligence Committee, the committee leadership is appraised of that so that it will be aware of possible attempts to peneiltrate the committee.

The interpretation given by the committee statement and by Sen. Hart was sharply different from impression left by Inouye on two White House staff members and at least five House or Senate leaders at the Tuesday morning White House breakfast.

One source said flatly that Inouye had told the group that some members of the committee were under surveillance. A second said that the "surveillance" - the exact word used by Inouye - was without the knowledge of members of the committee, while a third said he got the impression that the members had asked for it voluntarily.

One member of the committee, however, who asked no to be identified, said the full committee had never discussed whether it wished to be placed under surveillance and there was certainly no voluntary acceptance of it - if it had occurred - by the committee as a body.