Ronald Reagan said yesterday that he will announce his first Cabinet nominees today, and there were indications that the initial group will include roughly half of the posts to be filled.

The president-elect, returning for his second familiarization tour of Washington, did not indicate how many of his Cabinet choices, or which ones, will be announced today.

Reagan reportedly has decided to name his personal attorney, William French Smith, attorney general, and Caspar W. Weinberger, former chief of the Office of Management and Budget, secretary of defense.

Gen. Alexander M. Haig Jr. still appears to be Reagan's choice for secretary of state, although some advisers had counseled that Haig, because of his role in the Nixon White House, would be likely to stir controversy in Senate confirmation hearings -- too high a price for the fledging administration to pay.

A document in which former Watergate prosecutor Leon Jaworski hails Haig as an "unsung hero" of Watergate and the "moving force" in persuading Richard M. Nixon to resign has been circulating in Washington, however. In an unpublished interview with the editor of Armed Forces Journal that was made public by United Press International, Jaworski added that Haig might deserve to be president someday.

Other choices reportedly decided are: Sen. Richard Schweiker (R-Pa.), Reagan's 1976 vice presidential choice, for health and human services; William Casey, Reagan's 1980 campaign chairman, to head the Central Intelligence Agency; Drew Lewis, a Reagan supporter on the Republican National Committee, for transportation, Rep. Dave Stockman (R-Mich.) as director of the Office of Management and Budget, and Malcolm Balridge, who led the campaign of Vice President-elect George Bush in Connecticut, as commerce secretary.

Some sources said Betty Murphy, a former head of the National Labor Relations Board, is the choice for labor, but others said security checks have been started on another candidate, Ray Donovan, a contractor who headed Reagan's campaign effort in New Jersey.

In addition, Jewel Lafontant, a former deputy solicitor general, was reported the leading contender for housing and urban development, and Donald T. Regan, chairman of Merrill Lynch and Co., was a leading candidate for treasury secretary.

In the last week, Reagan's top aides have become defensive in the face of questions about the Cabinet selection process, and the president-elect seemed irritated yesterday when he encountered a barrage of questions from reporters.

"You all keep pressing me about these announcements. You know, I don't know of anyone who's ever announced any this early," Reagan told reporters as he boarded his Air Force jet at New York's La Guardia Airport for the flight to Washington.

Questions have multiplied as the Reagan team has fallen behind the schedule it initially set for forming a Cabinet, and the president-elect has given contradictory signals as to how many decisions he has made and whether he is getting his first choices.

Two days after his Nov. 4 victory, Reagan told his only post-election press conference that "we hope by late November, Early December, to be able to announce our choices for the Cabinet."

Edwin Meese III, who is heading Reagan's transition team and who is the designated White House counsel, told reporters the following day that Reagan planned to name his Cabinet by the last week of November or the first week of December.

These early statements raised expectations, but as Reagan aides have taken to saying, the timing of the Reagan announcements is in the same ballpark with that of his Democratic and Republican predecessors. In 1968, Richard M. Nixon also chose Dec. 11 to make his first announcement, but on that day he named his entire Cabinet. In 1976, Jimmy Carter made his first Cabinet nominations on Dec. 3 and his last on Dec. 24. In 1960, John F. Kennedy announced his first Cabinet choices Dec. 1 and his last on Dec. 16.

Reagan spent yesterday in private meetings after arriving from New York, where he had stopped for a day en route from Los Angeles.

Unlike his first post-election visit to Washington last month when he was photographed and cheered as he toured the Capitol, Supreme Court and White House, Reagan stayed in Blair House across from the White House most of yesterday.

His two stops were at Republican National Committee headquarters for a meeting with Chairman Bill Brock and at the Capitol Hill Club for a luncheon. Brock is reported in line for a sub-Cabinet post.

At Blair House, Reagan and Vice President-elect George Bush received black and Hispanic supporters and conferred with the top aides in the transition. Meese and White House chief of staff-designate James Baker III, who have been working from Washington while Reagan spent the last two weeks in California, led the aides participating in the staff meetings.

Reagan's schedule today includes a briefing on national security affairs, a meeting with transition staffers, lunch with the ranking Republican members of the House and one-on-one meetings with a number of senators, including Democrats Henry M. Jackson (Wash.) and John C. Stennis (Miss.) and Republicans Jesse Helms (N.C.) and Bob Dole (Kan.), as well as a session with black leaders.