WASHINGTON (AP) _ President Reagan on Tuesday nominated former Interior Undersecretary Ann Dore McLaughlin to succeed William E. Brock as secretary of labor and bring a woman back into his Cabinet.

Reagan called Mrs. McLaughlin, who also has held senior roles in the Treasury Department and the Environmental Protection Agency, a women of ''uncommon experience and competence ... who has won my full confidence and support.''

With only 15 months remaining in the administration, there appeared to be little sentiment among Democrats and labor unions for opposing the nomination.

''We're going to take a pretty good look at her, but it doesn't seem like she's drawing any serious opposition,'' said Paul Donovan, a spokesman for the Senate Labor and Human Resources Committee.

Sen. Edward M. Kennedy, D-Mass., the committee chairman, said through aides that hearings on the nomination would be expedited once all the paperwork reaches Capitol Hill.

Kennedy added: ''I would be delighted to see her follow in the footsteps of Bill Brock or (President Franklin D. Roosevelt's Labor Secretary) Frances Perkins,'' the first woman in a president' Cabinet.

Sen. Orrin G. Hatch of Utah, senior Republican on the Labor and Human Resources Committee, called the choice of Mrs. McLaughlin ''an inspired one. Ann has the ability and background to run the department.'' He added that ''she is well-respected and her experience in government will bring a special expertise to the Labor Department.''

Mrs. McLaughlin gave up the No. 2 post in the Interior Department, a job she had held for three years, last March following several clashes with Interior Secretary Donald P. Hodel.

''When I left your administration earlier this year, I had no idea I would be back so soon,'' Mrs. McLaughlin, 45, told Reagan in a White House Rose Garden ceremony announcing her nomination.

Neither Reagan nor Mrs. McLaughlin addressed any issues facing the department, including a large backlog of pending regulations in the Occupational Safety and Health Administration.

But, if confirmed by the Senate, she can be expected to lead the administration's fight against a broad agenda of legislation being pushed in Congress by labor unions.

Among more than a dozen bills moving through Congress are measures to raise the minimum wage, frozen at $3.35 an hour since 1981, to require 60 days advance notice of plant closings and large layoffs and to mandate employer- provided health insurance.

As Interior undersecretary, Mrs. McLaughlin reorganized government coal- leasing programs that had come under severe criticism while James Watt was secretary.

When Hodel became secretary in 1985, he began taking charge of some of the department's more controversial issues himself, such as oil drilling off the California coast.

Colleagues said Mrs. McLaughlin, who had been serving as the department's ''chief operating officer'' under Hodel's predecessor, William P. Clark, felt that the scope of her authority was being narrowed.

At the time of her resignation, she reportedly was being courted by the White House to succeed White House spokesman Larry Speakes. That job eventually went to Marlin Fitzwater, an associate of Mrs. McLaughlin when she help top press relations jobs in the Treasury Department and the Environmental Protection Agency.

Mrs. McLaughlin was communications director for President Nixon's re- election campaign in 1972 and his second inauguration in 1973.

Her husband, John McLaughlin, is a well-known conservative political commentator and television talk show host. ''If she handled John McLaughlin this long, she can handle anything,'' Reagan quipped Tuesday.

Brock, 56, announced his resignation three weeks ago to become the campaign manager for Senate Republican Leader Bob Dole's bid for the Republican presidential nomination in 1988. Dole, of Kansas, is scheduled to formally declare his candidacy Monday.

Brock is the second Cabinet official to join Dole's campaign. In September, Transportation Secretary Elizabeth Dole resigned to focus on her husband's presidential bid, leaving Reagan's Cabinet without a woman.

Within a week of Brock's resignation, White House officials had developed a short list of possible replacements down to five women, according to sources who declined to be quoted by name.

In addition to Mrs. McLaughlin, they included former Housing and Urban Development Secretary Carla Hills; Federal Communications Commissioner Patricia Diaz Dennis; Office of Personnel Management chief Constance Horner and former National Labor Relations Board Chairwoman Betty Southard Murphy.

The AFL-CIO took a benign approach to the nomination even though it expects Mrs. McLaughlin to continue Brock's role of leading the administration's opposition to virtually all of the labor group's legislative agenda.

''We know of nothing to recommend her nor nothing to oppose her on,'' said Rex Hardesty, a spokesman for the 14.2 million-member labor federation. ''So the AFL-CIO looks forward to working with the new secretary.''

With Democrats holding a 54-46 majority in the Senate, lobbyists for business groups said the AFL-CIO could block Mrs. McLaughlin's confirmation if it wanted.

''It appears that she was the least controversial of the candidates,'' said Pete Lunney, a lobbyist and labor relations specialist for the National Association of Manufacturers. ''My guess is that she will be no less vocal than Mr. Brock was in oppossing most of labor's bills.''

Jay Power, an AFL-CIO lobbyist, described Mrs. McLaughlin as ''a complete unknown to us. I'm sure it's going to be a delightful confirmation hearing to see what her views are.''

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