Defense Secretary Caspar W. Weinberger has decided to resign because of the deteriorating health of his wife, Jane, and President Reagan is expected to name national security adviser Frank C. Carlucci as the new defense secretary,

administration officials said last night.

The president is also considering appointing Army Lt. Gen. Colin L. Powell, the deputy national security adviser, to succeed Carlucci, the officials said. Before coming to the White House, Powell served as military assistant to Weinberger.

The officials said an announcement of the changes may come as soon as today, when Reagan is planning to announce a new secretary of labor. Weinberger, whose wife is suffering from cancer and severe arthritis, was unavailable for comment last night following a report on his plans by NBC News. Two weeks ago, asked about another news report that he planned to resign, Weinberger dismissed it as "the same reports" of resignation that persisted in earlier years.

Weinberger, 70, has held a powerful seat in Reagan's Cabinet, enhanced in part by his long personal relationship with the president and his easy access to the Oval Office. As defense secretary, Weinberger served as a strong advocate for Reagan's ambitious $2 trillion rearmament program, even in the face of growing pressure for cutbacks from a Congress worried about the deficit.

Aided by former Assistant Secretary Richard N. Perle, Weinberger was also a frequent opponent of arms control proposals advocated by Secretary of State George P. Shultz, and he was particularly forceful in resisting limits on the president's missile defense program, the Strategic Defense Initiative (SDI).

While officials said Weinberger's departure is not the result of pressure from within the administration, it may presage a new approach to arms control in the final year of Reagan's presidency. Carlucci, who previously served as deputy defense secretary under Weinberger, is known within the administration as a more pragmatic and flexible policymaker than Weinberger on arms control issues.

The shift comes at a critical time as Reagan makes final preparations for signing a treaty next month with Soviet leader Mikhail Gorbachev eliminating medium-range and shorter-range missiles in Europe. The agreement is the first major arms control treaty of Reagan's presidency and is to be signed at the first U.S.-Soviet summit in this country since 1973.

Even more important, Reagan and Gorbachev seem to be approaching intensified bargaining aimed at an agreement cutting strategic nuclear arsenals in half. A critical factor will be Reagan's response to Soviet insistence that restrictions be imposed on development and deployment of a space-based missile defense system as part of any accord on reducing offensive weapons.

Weinberger has refused to accept restraints that could slow the SDI missile defense program, now in research, and he oversaw a major expansion in its spending.

Powell, 50, has received high marks from White House officials while serving as Carlucci's deputy. One administration source said "it would make sense" for Reagan to appoint Powell to succeed Carlucci. If appointed, Powell would become the first black ever to hold the post.

Close acquaintances said Jane Weinberger's health has been deteriorating steadily in recent months. She recently completed a series of radiation treatments for the malignancy and has had persistent problems with arthritis that have occasionally left her bedridden, they said.

The couple, who celebrated their 45th wedding anniversary in August, recently sold their huge McLean residence and moved into a two-suite accommodation at the Watergate apartments because they could not install an elevator for her in the McLean house, acquaintances said.

For at least the past year, Jane Weinberger has spent most of her time at the couple's Bar Harbor, Maine, home while her husband remained in Washington.

Jane Weinberger, who writes children's books and runs a small publishing firm, has shunned the Washington political and social circuit that her husband relishes, and tried to persuade him to turn down the offer for a second term as defense secretary, according to friends.

"She has always wanted him to leave the job," said one acquaintance.

If Weinberger had remained in office until next March, he would have surpassed Robert S. McNamara as the longest-serving defense secretary.

"I'm surprised he's leaving before passing the mark McNamara made," said one close acquaintance. "He's never said that was a goal, but he has enough interest in his place in history to have served out the full {second} term."

In Monterey, Calif., a Pentagon spokesman, Fred S. Hoffman, said "no comment" when asked about Weinberger's resignation. When reports of Weinberger's potential resignation surfaced two weeks ago, Hoffman vehemently denied the reports, calling news organizations to refute a CBS News broadcast even before it aired.

Weinberger arrived in Monterey yesterday with his wife and held a news conference on the new medium-range missile treaty. Then he met informally with defense ministers from the North Atlantic Treaty Organization who are meeting there.

Reagan frequently took Weinberger's advice over that of White House and State Department officials. The secretary first came to work for Reagan two decades ago after a difficult period in Reagan's first year as California governor. Weinberger was recruited to be state finance director, and later served as budget director and secretary of health, education and welfare in the Nixon administration. Carlucci was Weinberger's deputy at the time.

Weinberger and Shultz were top officials of Bechtel Group Inc. before Reagan was elected president.

Weinberger was selected as part of Reagan's original Cabinet, and over the years has advocated a selective use of military force.

For example, in 1983 Weinberger expressed reservations about the deployment of Marines as a peacekeeping force in Lebanon. That deployment led to the largest single loss of military troops in the Reagan years when a suicide truck bomber killed 241 servicemen at the Beirut Marine headquarters.

In contrast, Weinberger has been perhaps the most vocal supporter of the administration's controversial Persian Gulf policy of reflagging Kuwaiti oil and gas tankers, and protecting them with U.S. military escorts. Weinberger was an early and frequent opponent of what he called Reagan's "absurd" decision to sell American weapons to Iran.

Although the defense budget declined slightly in the last two years after a sharp rise during Reagan's first term, Weinberger steadily battled for modernization of the strategic forces, including the B1 bomber, MX missile and Trident submarine. Both the B1 and the MX have run into major problems.

Weinberger earned a reputation for fealty to the president's wishes, even when he initially had doubts about a policy. For example, before Reagan publicly launched the missile defense program in March, 1983, Weinberger had written a letter expressing doubts about it, but he later became one of the most ardent boosters of SDI.

Weinberger's close associates say he will most likely divide his time among Washington, San Francisco and Maine in the coming months, making television appearances and writing commentaries for magazines and newspapers. Sources said he also has received several book contract offers.

Staff writer R. Jeffrey Smith contributed to this report.