Chief Justice-designate William H. Rehnquist yesterday denied allegations that he challenged voter credentials in minority precincts in Phoenix in the early 1960s, telling the Senate Judiciary Committee that those who have recently said he did were mistaken.

He said he stood by his 1971 statements to the committee, which have been disputed by about a dozen witnesses. He said that while his memory had grown "faint," he "did not believe" that he had approached minority voters and demanded that they prove their literacy by reading portions of the Constitution.

In an unexpected disclosure, Rehnquist acknowledged under questioning that a deed on the Vermont vacation house he bought in 1974 contained a restrictive convenant prohibiting lease or sale of the property to "any member of the Hebrew race."

Rehnquist testified that, although he thought he had read the deed, he was unaware of the illegal and unenforceable restriction until a few days ago. "I was amazed" to learn of it, he said. Sen. Patrick J. Leahy (D-Vt.) pointed out the deed was a printed, "basically boilerplate" document with the restriction prominently typed in.

"I think it's unfortunate to have it there," he told Leahy, who revealed the restriction after it was discovered by the Federal Bureau of Investigation. Asked whether he would have it removed, Rehnquist said, "I don't know exactly what the point would be . . . other than that it is quite obnoxious."

But under further prodding from Leahy, Rehnquist said, "If there is a procedure under Vermont law where one could void it or get rid of it, I would certainly go through it."

Rehnquist, speaking to another issue raised yesterday during a full day of testimony at his confirmation hearings, asserted that despite his record as a lone dissenter and staunch conservative in court decisions, he "should not have any problems" fulfilling the chief justice's traditional role as leader of the court and of the federal judiciary.

Rehnquist said he has been writing fewer separate opinions and has dissented alone less frequently in recent years than when he joined the court in 1972. "I have tried to restrain myself lately," he said. "In the past five years, Justice John Paul Stevens has filed lone dissents more than I have. And he is a centrist."

The deed, the Phoenix dispute and a controversy about the accuracy of his 1971 statements concerning a memo opposing school desegregation he wrote 34 years ago as a Supreme Court law clerk were among the issues raised yesterday during the first day of questioning.

Rehnquist stood by his 1971 statements about the memo he wrote as a clerk to Justice Robert Jackson in 1952. In the memo, Rehnquist took the view that the "separate-but-equal" doctrine of racial segregation should not be overturned.

During the 1971 floor debate and again yesterday Rehnquist said the views in the memo were not his but Jackson's. He said he felt the separate-but-equal case, Plessy v. Ferguson, was "wrong" and "not a good ruling" but said he had not "reached a conclusion" about how he would have voted in the case that overturned it, Brown v. Board of Education.

Sen. Joseph R. Biden (D-Del.), the committee's ranking Democrat, pressed Rehnquist to give his personal views on the case: "Aren't you able to give me a more definitive answer as to how you felt at the time?"

"Law clerks don't have to vote," Rehnquist noted.

"But they have to think," Biden said.

Much of the testimony yesterday focused on recent allegations that Rehnquist had not been candid with the committee in 1971 in recounting his role as a Republican Party stalwart in Phoenix in the late 1950s and early 1960s.

Rehnquist said he was "testifying from a much fainter recollection" than he had in 1971 when he categorically denied such activities in a letter to the committee during his confirmation as associate justice on the court.

Committee Chairman Sen. Strom Thurmond (R-S.C.) said yesterday that the FBI had uncovered "absolutely no new information" beyond that available when the Senate confirmed Rehnquist as an associate justice. The committee in 1971 found the allegations "unsubstantiated," but no witnesses were called or testimony taken.

Thurmond said 10 persons who had been in Phoenix in the 1950s and early 1960s will be called to testify on Friday regarding allegations that Rehnquist personally challenged minority voters at the polls there, particularly during the 1962 election.

The FBI report, assembled at the insistence of committee Democrats, was not made public. One committee Democrat, Sen. Dennis DeConcini (Ariz.), told reporters that the report has several statements "on both sides of the issue. Some say they saw him challenge, some say they simply saw him at the heavily minority precincts and some say that they saw him and he wasn't challenging voters . "It's enough to give you concern," said Deconcini. "But I think it is very difficult to conclude on the basis of contradictory statements 24 years ago that this man should not sit as chief justice of the United States."

Some of those who will be called to testify include Phoenix lawyers who formerly were Arizona Democratic Party officials. They have alleged that Rehnquist was part of a concerted GOP effort to harass and intimidate minority voters.

In addition, Democrats said they plan to question two former federal prosecutors in Phoenix who at the time investigated allegations of illegal activities by the Republicans.

Rehnquist said it was "conceivable" that he may have challenged a voter during the early 1950s, when he acted as a poll watcher, saying his memory was not that good. But he insisted that he never harassed or intimidated voters. "I categorically deny that," he told Sen. Edward M. Kennedy (D-Mass.).

Kennedy read from detailed statements by of five witnesses who contradicted Rehnquist's accounts of his role in GOP "ballot security" and related programs in Phoenix. "Why would they make these statements?" he asked. "What is their motivation?"

Rehnquist said he did not know, but said they were "mistaken" and answered Kennedy's rapid-fire questions -- which each began "Do you deny?" -- with equally swift denials: "Yes, I do deny that."

Sen. Howard M. Metzenbaum (D-Ohio), picking up on the same theme, said the issue is not whether Rehnquist acted improperly during those elections, but whether he had been candid in his answers to the committee in 1971 and whether he was being candid now.

Rehnquist said one report that he had pretended to photograph minority voters with an unloaded camera, allegedly to intimidate them, was "mistaken" and said he did "not recall" approaching voters and demanding proof of their literacy.

Sen. Paul Laxalt (R-Nev.) asked Rehnquist whether he felt that minorities and women's groups, several of which have recently come out strongly against his confirmation, "are going to be prejudiced by your being confirmed" as chief justice.

"No, I don't think so," Rehnquist said, adding that he had "no bias, blatant or otherwise," against those groups. Rehnquist said the positions he has taken narrowly interpreting due-process and equal-protection provisions of the Constitution may have been contrary to the positions taken by women and minorities. But he said they were also sometimes contrary to the views of corporations as well.

He noted that he had written the majority opinion in a sexual harassment case last month that was cited by feminist groups as a major victory.

Before Rehnquist's testimony, two officials from the American Bar Association told the committee that Rehnqhist had received its highest rating of "well qualified" to succeed Warren E. Burger as chief justice.

That rating, one official told the committee, is reserved for candidates who met the "highest standards of professional competence, judicial temperament and integrity."

Rehnquist's fellow justices showed "an almost unanimous feeling of joy at his appointment," another ABA official said, adding that the justices, all of whom were interviewed, said they have the highest regard for him. Even one of those who have often opposed him, the official said, "looks forward to a tremendous improvement in the quality of the court's work" and thinks Rehnquist would "pull the court together."

Washington lawyer Joseph L. Rauh Jr. denounced the ABA testimony as soon as the committee broke for lunch. "Is this the same committee that said Supreme Court nominee Harrold Carswell was well qualified?" he demanded of the two officials.

Rehnquist also faced questioning about his 1972 refusal to disqualify himself from an Army surveillance case before the court. As a Justice Department official during the Nixon administration, he had told a Senate subcommittee in 1971 that he didn't think the case had any place in the courts because none of those watched had been hurt.

Rehnquist said yesterday there would "probably be very strong grounds for disqualification" now in light of a new federal law.