The Reagan administration's new antitrust chief has started his tenure with a managerial bang, but has made no noise about his plans for handling a number of policy issues lying ahead this fall, ranging from the Conrail sale to sports law.

Douglas H. Ginsburg, a proponent of industry deregulation and the administration's free market policies, was sworn in early this month as assistant attorney general for the Justice Department's antitrust division.

Ginsburg served from 1983 to 1984 as deputy assistant attorney general for regulatory affairs under former antitrust chief William F. Baxter, and headed the regulatory policy staff at the Office of Management and Budget before returning to Justice.

Ginsburg has not yet held a news conference or granted interviews to discuss his plans for the antitrust division. But a few days after starting the job, he announced a department reorganization that indicates he will continue the administration's antitrust policies, which have stressed the importance of economic efficiency and foreign competition in evaluating proposed mergers of large corporations.

His plan for reorganizing the antitrust division, subject to OMB review and congressional approval, would elevate the status of the division's economists and would formally integrate international trade activity with domestic industry litigation.

In a memorandum to the antitrust staff, Ginsburg said he proposed the reorganization "only because I am utterly convinced that it will improve our ability to do our jobs -- to enforce the antitrust laws, develop competition policy in a rapidly changing international environment and effectively advocate competitive solutions to domestic market problems."

The division's staff has been cut by about 35 percent since 1981, with no change in organizational structure. "As a result, the ratio of supervisory to nonsupervisory personnel has ballooned," Ginsburg said in his reorganization proposal. To improve efficiency, Ginsburg's plan would consolidate the number of litigating teams in the Washington headquarters to five from the current nine. The plan would not change the size of the current staff, and would not affect the division's seven regional offices.

Ginsburg proposes elevating the current economic policy director to a deputy assistant attorney general for economic analysis as "a recognition of the fact that economists properly have a role equal to that of lawyers in the development of antitrust policy and in the enforcement of the antitrust laws."

The plan would strip the foreign commerce section of its litigation responsibilities and distribute them among other litigation sections according to industry and commodity.

The change "recognizes that, in an increasingly international economy, an ever larger proportion of the division's litigation has international aspects and it is therefore inappropriate, if not impossible, to continue to assign international enforcement matters to a single section," Ginsburg said.

Ginsburg's new organization will face a number of issues this fall:

*On Conrail, the division will continue to review the government's proposed sale of Consolidated Rail Corp. to Norfolk Southern Corp. Justice has said that the merger would hurt competition unless Norfolk Southern sells certain rail lines to create long-term, viable railroad service along those routes. Once Norfolk Southern has arranged the divestitures, Justice would have to approve them for the merger to go through.

*Pan American World Airways' plan to sell its Pacific routes to United Airlines Inc. may violate federal antitrust laws, Justice said in May. Since then, a Justice Department economist said at a Department of Transportation hearing that the sale should be approved if some of the routes are sold to a viable airline competitor capable of providing long-run service from the United States to Tokyo and Hong Kong. Justice's formal position on the proposed sale is due tomorrow.

*Justice will continue to monitor congressional debate about several proposals to grant antitrust exemptions to professional sports leagues. The department reversed its previous policy in June by saying it would not object to granting antitrust immunity to pro league efforts to prevent team relocations. However the department opposed four proposed bills that would grant other antitrust exemptions to the leagues.

On a broader policy scale, Ginsburg inherits an agenda from his predecessors as well as the chance to leave his imprint on federal antitrust law.

His immediate predecessor, J. Paul McGrath, said before his resignation in April that the antitrust division's "No. 1 priority, chronologically," will be to push for changes in laws governing the licensing of patented inventions, to allow companies more flexibility and to provide greater patent protection.

McGrath also called for changes in treble-damage penalties, rules that allow parties injured by antitrust violations to sue and recover three times the damage suffered. He said he would retain the penalty for secret price-fixing, but would throw it out for violations of antitrust rules governing joint ventures, licensing and vertical price agreements.