Richmond Circuit Court Judge James E. Sheffield, nominated by President Carter to become Virginia's first black federal judge, abruptly halted his own Senate confirmation hearings yesterday as he was about to be questioned about three criminal investigations into his alleged tax problems.

Saying he had been denied complete access to information on the investigation, Sheffield asked that Senate Judiciary Committee hearings on his confirmation be postponed until he could review all FBI and Justice Department files on the matter.

The files already have been made available to the committee.

Though Sheffield declined to discuss the nature of the government investigations, which he acknowledged he was aware of, sources familiar with the probes said they involved three separate criminal investigations into the Richmond judge's tax transactions over the last 10 years.

None of the investigations, resulted in charges, nor did they involve activities since Carter nominated Sheffield to the federal bench last April. a

The 43-year-old Sheffield has become the focal point in a nearly three-year controversy over the filling of four new federal judgeships in Virginia.

The Carter administration, under pressure from prominent black leaders, is determined that one of the four appointees will be black. But the state's senior senator, Harry F. Byrd Jr., has insisted the nominees be made from a list of 10 white males he submitted to the White House for consideration.

Committee aides said yesterday they did not know whether the White House had been fully aware of the investigations into Sheffield's tax problems at the time his nomination was announced. A White House press officer said the Carter administration would have no comment on the confirmation hearings.

Sen. Joseph R. Biden (D-Del.), who presided over yesterday's hearing, stressed that despite the tax investigations the Justice Department had recommended Sheffield's appointment.

"I know of no charges against you that I am aware of," he told Sheffield. "There are just questions that the staff and some committee members have after reading the Justice Department files."

Sheffield met with Justice Department officials Monday afternoon to make an inventory of files turned over to the committee. He said he was shown one file -- compiled by the Internal Revenue Service, it was later learned -- but told that he could not examine its contents.

The man ready to ask the questions yesterday was Sen. Orrin G. Hatch (R-Utah), who alluded to Sheffield's tax problems throughout the morning as a succession of witnesses testified in favor of the nominee.

Besides any tax questions, Sheffield's nomination faces formidable opposition from Byrd. Arguing that he followed selection procedures suggested by the White House, Byrd has invoked the tradition of "senatorial courtesy" in opposing the nomination.

But blacks and others who testified in Sheffield's behalf said yesterday that the 65-year-old Byrd, heir to a political dynasty in Virginia, was upholding another tradition of the Old Dominion; unequal treatment for blacks and other minorities.

"The name Sen. Harry Byrd represents to the people of Virginia the era of massive resistance," shouted Oliver W. Hill, a black attorney from Richmond long active in civil rights struggles in the state.

Pounding the table at one point -- and with Byrd sitting just a few feet behind him -- Hill accused Byrd of betraying blacks by his attempt to block Sheffield's appointment.

"He promised us out of his own mouth that if he was reelected, we'd have a new day in Virginia and that he'd help to bring it about," Hill said.

Several black leaders complained that the two commissions on which Byrd relied in recommending nominees from the state's eastern and western judicial districts virtually ignored any meaningful consideration of black or women candidates.

"This nomination is hampered by the single explanation that the nominee is a man of color," argued Wiley F. Brandt, dean of the Howard University Law School, from which Sheffield graduated.

Jack Gravely, executive director of Virginia's National Association for the Advancement of Colored People, said he had no objection to the appointment of the three white males nominated from the Byrd list. But he complained that his group and other organizations with strong community ties "never heard from these so-called broad-based commissions" which selected and screened candidates.

Noting that Byrd had refused a White House request to expand his list to include at least one black candidate, Gravely said Virginia's senior senator was more interested in perpetuating the state's white power structure than in opening up the judicial system to blacks and other minorities.

Recalling what his coal miner father used to "yell" at his mother, Gravely said he had grown up in Virginia mindful of the saying: "Don't bet against the Dodgers, don't curse on Sundays and don't vote for a Byrd."

The two commissions, composed largely of white male attorneys, two blacks and one woman, considered Sheffield's nomination but never interviewed him. The three whites who made the list and were subsequently nominated by Carter are State Sen. Harry J. Michael of Charlottesville, James P. Jones of Abingdon and Richard L. Williams of Richmond. None is a sitting judge.

Byrd, who introduced all four nominees to the Senate committee, vowed to do everything in his power to block Sheffield's appointment.

"It is never very pleasant, of course, to fight the president of the United States . . . but I feel there is a basic principle involved here," he said.

Byrd told the committee he had faithfully followed procedures outlined in a handwritten letter he received from Carter in March 1977. The letter recommended the establishment of judicial advisory commissions to screen judgeship candidates on the basis of merit, not political connections.

The Virginia senator said he followed the recommendations, named the commissions and submitted their suggested candidates, even though he was "personally disappointed" when two of his favored candidates did not make the list.

"The senator from Virginia did cooperate; the senator from Virginia did use the selection commission process," Byrd said. Saying he stood "foursquare" behind the commissions' recommendations, he asked the committee to confirm the nominations of Michael, Jones and Williams but to reject Sheffield's "as the commission in a unanimous decision did not consider him to be among the best qualified."

Virginia Rep. Herbert E. Harris II urged the prompt confirmation of all four nominees, saying the delay had already caused a heavy court workload and backlog of cases.

Virginia's freshman Sen. John W. Warner -- despite GOP suggestions that the confirmations should be held up in anticipation of a Ronald Reagan victory this fall -- also asked for speedy consideration of the appointments. But he withheld his support of Sheffield and Michael pending the outcome of the hearings.

Sheffield said after the hearing that he hoped to receive copies of the Justice Department files, particularly IRS information denied him thus far, via the Senate committee in the next few days. He said he hoped to reschedule his hearing "within five days" of seeing the files.

Sen. Edward M. Kennedy, who chairs the Judiciary Committee, has treated the Virginia's judgeships as "a package deal" since the controversy over the appointment of a black judge first surfaced. It was unclear yesterday whether the committee would proceed with the confirmation of the three other nominees -- whose hearings went relatively smoothly -- until Sheffield has had a chance to testify.