Supporters of William Bradford Reynolds rallied to his defense -- and opponents cited new allegations of misleading testimony -- as the Senate Judiciary Committee prepared to vote today on his nomination as associate attorney general.

Critics said that internal Justice Department documents contradicted Reynolds' claim that he sided with civil rights groups in two cases involving housing and sex discrimination. The documents show that Reynolds, head of the department's Civil Rights Division, initially argued against the department's stance in both cases.

Sen. Orrin G. Hatch (R-Utah), Reynolds' most outspoken defender on the committee, said the charges by Reynolds' opponents amounted to "a tremendous effort at character assassination."

"I do resent the vicious attacks against Reynolds by opposing groups," Hatch said in an interview yesterday. He said the nomination fight had become "dirty" and that some civil rights groups were "hitting below the belt."

"I think it's ridiculous to pick three to 10 cases out of the air . . . out of 60,000 to 70,000, and to impute a lack of credibility to him," Hatch said. "The few instances where [opponents] feel he was not as forthright as he might have been, or where he's admitted his recollection was faulty, each of those can be explained away. They are matters that are ambiguous; you ought to give the nominee the benefit of the doubt."

Reynolds' prospects for confirmation dimmed after senators accused him of misleading the panel about his role in a series of voting rights cases. He later apologized for any misunderstandings.

Ralph G. Neas, director of the Leadership Conference on Civil Rights, took issue with Hatch.

"Apparently he is attempting to blame the messengers for the problems that Mr. Reynolds has encountered in the Senate Judiciary Committee," Neas said. "But an examination of the hearing transcript would demonstrate conclusively that Mr. Reynolds' nomination is in deep trouble solely because of what he has said and done."

As "an example of not being candid with the Senate," Neas cited a June 18 hearing at which Hatch asked Reynolds to name any cases in which he sided with rights groups. Reynolds cited a 1982 Supreme Court ruling upholding the right of fair-housing investigators, or "testers," to sue landlords for racial bias. The case involved Havens Realty Corp. of Richmond.

Reynolds said that his department filed a friend-of-the-court brief supporting the use of testers and this "was something that the civil rights community was exceedingly pleased with."

But in a 1981 memorandum to the solicitor general, Reynolds opposed filing a brief. In a memo to his staff, he said that if anything, the department should argue against testers' "standing," or right to sue.

"Remote testers who can show neither community ties nor individual interest in the apartment complex advertised . . . probably should not have standing," he said.

Reynolds also argued in part that the case was moot because the victims had gotten relief. He said the best the lawsuit could produce was "a Fair Housing Act precedent" and that this was "a questionable excuse" for pressing the case.

Under questioning by Sen. Charles McC. Mathias Jr. (R-Md.), Reynolds said he decided to support the use of testers after the solicitor general's decision to file the brief. He said he signed the brief "because I felt that was the position we should be taking."

A second case Reynolds cited in his defense involved a Supreme Court ruling last year that law firms are subject to sex-discrimination laws when deciding who moves up to partner. The case was filed by Elizabeth Anderson Hishon against her former employer, the Atlanta law firm of King & Spalding.

Reynolds said the department filed a friend-of-the court brief challenging an appeals court ruling that partnership decisions are exempt from civil rights law. But in a 1983 memorandum to his staff, Reynolds called the appeals court ruling "correct" and said that "I disagree with [the] view that the Title VII law covers partnership decisions."

Questioned by Sen. Edward M. Kennedy (D-Mass.), Reynolds said he later changed his mind and supported Hishon's position in his formal memo to the solicitor general.

"When I first read the decision, that was my initial reaction, and on further review and analysis of the law in this area, I came out on the side that we argued in the Supreme Court," Reynolds said.

Former attorney general Griffin B. Bell, a partner in King & Spalding, is among those who defended Reynolds. He argued in a column published yesterday in The Washington Post that it was "unreasonable and unfair" to focus on "petty factual reconstructions."

"The fact is that Reynolds is under attack because of the Justice Department's policies on quotas and discrimination -- nothing more, nothing less," Bell wrote.

The panel delayed action last week after it became clear that at least nine of its 18 members would vote against Reynolds. Supporters were expected to try to send the nomination to the floor without a recommendation.