In his two weeks on the job, Labor Secretary William E. Brock has begun assembling his management team, announcing four major appointments and planning a fifth, according to sources, with the expected nomination of White House aide Michael Baroody as assistant secretary for policy.

More than half the department's 16 top political jobs had been vacant at various times in the final months of former secretary Raymond J. Donovan's tenure. But the disarray at the department is gradually disappearing as Brock moves to fill the jobs, some of which had been vacant for extended periods.

As expected, Brock, the former U.S. trade representative, has brought along several key USTR staff members to fill top jobs. They include Dennis E. Whitfield, his new chief of staff; David F. Demarest Jr., as deputy undersecretary for public and intergovernmental affairs, and William J. Maroni, as deputy undersecretary for congressional affairs.

Whitfield, a Georgia native, worked for Brock as director of political affairs at the Republican National Committee before moving with him to the USTR. Demarest, 33, another RNC alumnus, will oversee public information activity and supervise the 10 regional representatives who handle relations with local governments, industry and labor unions. Maroni was a legislative assistant to Sen. John H. Chafee (R-R.I.) before coming to the USTR to work on congressional affairs.

Brock's only controversial appointment to date has been Stephen Schlossberg, former general counsel of the United Auto Workers, to be deputy undersecretary for labor-management relations. The appointment drew fire from the National Right to Work Committee, which accused Brock of giving unions too much clout within the department by naming Schlossberg. Brock brushed aside the criticism, saying that the choice of a respected former union official is important for a job aimed at promoting cooperation between unions and employers.

Baroody, who worked under then-White House aide Michael K. Deaver as a deputy assistant to President Reagan for public affairs, is a former RNC communications director. His father, William J. Baroody Sr., and his brother, William Jr., have headed the American Enterprise Institute.

A big question to Labor-watchers is how soon Brock will move to replace Robert A. Rowland as the assistant secretary in charge of the Occupational Safety and Health Administration. Brock has moved quickly to mend fences with the AFL-CIO and other unions, and the replacement of Rowland has been high on the agenda of organized labor, which accuses Rowland of being too cozy with employers.

Brock said in an interview yesterday that he plans to meet with Rowland soon to discuss OSHA and Rowland's future at the agency. But Brock said that his review of OSHA and other agencies will take "a few more weeks" and that "evidence of changes may take a little longer."

Among those whose future at the department will be decided shortly are undersecretary Ford B. Ford, who ran the agency while Donovan took a six-month leave to fight his indictment on criminal fraud charges, and solicitor Francis X. Lilly.

Brock has one additional vacancy to fill, with the surprise resignation last week of Patrick J. O'Keefe, the deputy assistant secretary for the Employment and Training Administration, which oversees the department's biggest programs, totaling nearly $25 billion a year.

O'Keefe, who is leaving to become executive vice president of the New Jersey Builders Association, has functioned as the chief operating officer under assistant secretary Frank C. Casillas in the division, which oversees state unemployment programs, the $4.5 billion Job Training Partnership Act, the displaced workers program and more.

O'Keefe's job has been a hot seat in the past 18 months, with intense competition for some $40 million in discretionary job-training funds and with widespread debate over the federal role in job training. The JTPA gives state and local governments more decision-making power -- but less money -- than did the Comprehensive Employment and Training Act.