Labor Secretary Raymond J. Donovan, fending off criticism that he has moved too slowly in taking control of his department, said yesterday that he plans to present a major departmental reorganization next month.

The secretary also said that "it's imminent" that the long-vacant undersecretary's slot at the Department of Labor will be filled, and that two candidates are under consideration for the job.

Albert angrisani, Donovan's chief of staff and assistant secretary for employment and training, had been the most likely choice for undersecretary, according to rumors. But Donovan said yesterday that the 31-year-old Angrisani, who he praised as a competent manager, is no longer under consideration for the post.

Donovan declined to give details on the rearrangement of his department. But one key department source suggested -- as Donovan did recently -- that the reorganization will be similar to one proposed by the conservative, Washington-based Heritage Foundation.

In its 1,093-page outline of governmental reorganization, Mandate for Leadership: Policy Management in a Conservative Administration, the foundation recommnded "a redirection of the department's focus," which the foundation said was characterized by "a general bias . . . in favor of organized labor" and "a general mistrust of the motives of business."

Donovan, who said in an earlier interview that suggestions for reorganization came from a variety of groups, including the Heritage Foundation, unions, and the Business Roundtable, yesterday dismissed widespread charges that his has become an anti-labor department. But he said that the functions of his agency will be guided by "a true belief in the free enterprise system."

This has brought him into conflict with AFL-CIO President Lane Kirkland and other labor leaders and liberal members of Congress like Sen. Edward M. Kennedy (D-Mass.), Donovan said.

"The people who do not share our philosphy have . . . a distrust of business," Donovan said. "They say that we are anti-worke, anti-poor, anti-old, and that the free enterprise system has had its chance to prove that it was responsible, and that it has failed. I reject that philosophy. Ronald Reagan rejects it," he said.

Accordingly, the secretary said yesterday, as he has before, that his department will seek accommodation and cooperation with business, rather than persist in what he called the department's past adversary relationship with business in matters such as occupational safety and health regulations and equal employment opportunity.

Donovan acknowledged that his approch constitutes "a marked philosophical difference" with his critics in organized labor, but added that organized labor's "fear of this administration, in certain quarters" is unwarranted.

"We're both after the same ends -- to protect and promote the welfare of the working man and woman. Some of the criticism laid at our doorstep is, at best, premature," he said.

On matters related to departmental organization, Donovan said:

He will retain and "will strengthen" the office of the assistant secretary for policy evaluation and research. ASPER is the department's economic policy arm, long rumored as a candidate for extinction under Donovan.

He will keep the women's bureau, but the function of the bureau, also rumored for extinction, "will be refocused." A bureau director, whom he declined to identify, has already been selected, Donovan said.

Angrisani will retain his chief of staff title, for the time being, depending on "how the undersecretary develops." At any rate, the leadership of the department will operate on a team concept in which Angrisani, who heads the department's largest division as employment and training assistant secretary, will be a major player.