President Reagan, his administration distracted by problems on other fronts and beset by internal conflict over his next nomination to the Supreme Court, has not yet decided on his choice, even though an announcement is scheduled for today, administration sources said.

Sources said the White House staff wants Reagan to nominate federal appeals court judge Anthony M. Kennedy of Sacramento, 51, a moderate conservative, but that the Justice Department is fighting hard for Douglas H. Ginsburg, a former department official who has been a judge on the federal appeals court here for less than a year.

Ginsburg, 41, is seen as more ideologically similar to Reagan's first choice for the vacancy, Judge Robert H. Bork, who was rejected by the Senate Friday.

As of last night, Reagan had not yet settled on a nominee, the sources said. He is to meet with Attorney General Edwin Meese III this morning to discuss the issue, and the White House has said the decision will be announced at 2 p.m.

However, that announcement could be delayed if Reagan decides he needs more time. The president's attention has been diverted by the continuing problems with the stock market and the budget deficit, the on-again, off-again prospects for a summit with Soviet leader Mikhail Gorbachev, and the death of his mother-in-law, Edith Davis.

Although the main debate yesterday involved Kennedy and Ginsburg, sources said another candidate, federal appeals court judge William W. Wilkins Jr., was being pushed strongly by Sen. Strom Thurmond (R-S.C.).

Kennedy, who is seen as a moderate conservative who will have an easier time winning confirmation, has the backing of most White House officials. Ginsburg, a former head of the Justice Department's antitrust division, is being supported by the more conservative faction within the administration, including Assistant Attorney General William Bradford Reynolds and T. Kenneth Cribb Jr., a top White House aide and former assistant to Meese.

"Meese wants one last say," one source said. However, that source said White House officials have settled on Kennedy and that the decision will be "finalized" this morning. Other sources cautioned that the outcome was not so clear and that the announcement could be put off.

Meanwhile, Thurmond has been urging the White House to nominate a southerner and has been pressing hard within the administration and among fellow senators for Wilkins, of Greenville, S.C. Wilkins heads the U.S. Sentencing Commission. However, Justice Department officials were unhappy with Wilkins' direction of the commission and both Justice and White House sources say they consider his nomination highly unlikely.

Kennedy, who knows Meese and other Reagan advisers from their days in California, was a well-known Sacramento lawyer and lobbyist before President Gerald R. Ford named him to the 9th U.S. Circuit Court of Appeals in 1976.

Ginsburg is a University of Chicago law school graduate who clerked for Supreme Court Justice Thurgood Marshall before becoming a professor at Harvard Law School, where he specialized in antitrust and banking law. Sources said Harvard delayed giving Ginsburg tenure for one year because some faculty members thought his academic writings were not adequate.

Ginsburg, an adherent of the law and economics movement that is closely identified with the University of Chicago, was a deputy assistant attorney general, administrator for information and regulatory affairs at the Office of Management and Budget, and then assistant attorney general for a year before being named to the appeals court last year.

As head of the antitrust division, he complained that judges had in too many instances let business figures convicted of antitrust violations off without prison sentences. "With discouraging frequency, the price-fixers and bid-riggers we do bring to justice slip off with token punishment," he said in a 1985 speech.

The American Bar Association committee that evaluates federal judicial candidates rated Ginsburg "qualified," the lowest of three acceptable evaluations because of concern that he did not have adequate trial experience.

A law student who interviewed for a clerkship with Ginsburg said he described himself as the most conservative official in the Justice Department during his tenure there. The student said Ginsburg said he liked to have at least one clerk who was a member of the Federalist Society, a conservative legal organization, in order to keep up on the latest intellectual trends in the law.

In his decisions on the appeals court, Kennedy has upheld a Navy regulation providing for discharge of those who engage in homosexual activities, overturned a decision requiring the state of Washington to pay its female employes based on the "comparable worth" of their jobs, found the one-house legislative veto unconstitutional, and backed the constitutionality of campaign contribution limits.

The tone of his opinions is markedly different from that of Bork's, who wrote often and eloquently about the importance of judicial restraint. For example, in the Navy case, Kennedy said the Supreme Court's earlier decisions on privacy -- including its 1973 abortion decision -- did not stretch to cover the case. But he did not criticize the privacy rulings as Bork did when he addressed a similar case.Staff writers David Hoffman and Al Kamen contributed to this report.