The Soviet Union and the Marxist government of Angola are shopping for an American public relations firm to improve their image in the American news media, according to several private consultants who have spoken with Soviet and Angolan officials in recent weeks.

Public relations executives, some of whom are wrestling with the ethical dilemma of representing governments hostile to the United States, see the Soviet contacts as the natural outgrowth of last November's summit talks between President Reagan and Soviet leader Mikhail Gorbachev. Disputes between Washington and Moscow on arms control, regional conflicts and other issues are likely to be played out publicly as both superpowers try to influence world opinion.

Efforts by Angolan officials to obtain public relations advice were seen by PR executives as a propaganda counterattack to the movement in Congress to provide millions of dollars in humanitarian aid and covert military assistance to rebels fighting the Cuban-backed Angolan regime.

Public relations executives were generally reluctant to discuss the exploratory contacts yesterday because of the substantial revenue the prospective clients could bring and because of what some see as prickly ethical questions.

Several sources said the Soviets had held discussions in the last week with three firms -- Burson-Marsteller, Gray & Co. and Hill & Knowlton -- while Angolan officials had talked with Burson-Marsteller.

At Hill & Knowlton, Washington vice president Bob John Robison said, "We were contacted by a Mr. Al Levine of the information department of the Soviet Embassy and asked if we were interested in discussing the marketing of certain information. He was told we do not represent foreign governments for political propaganda purposes."

A spokesman for the Soviet Embassy said the Soviet government historically has handled its own relations with the American news media and dismissed the reports that Soviet officials had met with U.S. public relations firms as "talk around town." The spokesman said there was no "Al Levine" listed among embassy personnel.

John Jessar, general manager of Burson-Marsteller, said he would not comment about prospective clients, but one insider there who asked not to be identified said that Soviet officials visited the firm's offices during the past week and discussed representation in "cultural and athletic" affairs.

"My feeling is they probably feel they don't understand the American media as well as they might," the insider said.

At Gray & Co., partner Frank Mankiewicz said that the Soviets had inquired about Gray's radio programming capability for "cultural" matters, but that talks still were preliminary.

"Their press relations are uniformly lousy," Mankiewicz said. "You would think that some Soviet ambassador would have told them by now that The Washington Post and Time magazine are not agents of the government, but when they see a story on the front page . . . they think that's the government of the United States speaking."

Mankiewicz said that he assumed the Soviets might want to go beyond "cultural" matters and "sooner or later" seek advice on foreign policy disputes between Washington and Moscow, such as regional conflicts and President Reagan's "Star Wars" antimissile defense. "I assume that's always in their minds," he added.

Dozens of countries -- both friendly and unfriendly to the United States -- retain U.S. law firms and public relations firms to look after their interests in Washington, where foreign aid bills in Congress and administration foreign policy initiatives can have a vital impact on foreign governments, economies and conflicts. Firms that do such work are required to disclose their employers to the Justice Department under the Foreign Agents Registration Act.

For instance, the Sandinista government of Nicaragua, which the Reagan administration has been trying to destabilize since 1981, has maintained regular representation in Washington to combat proposals for funding Nicaraguan "freedom fighters," as Reagan refers to rebel "contra" forces.

In Angola, the primary opposition group led by Jonas Savimbi and his UNITA organization retained a well-connected Alexandria firm, Black, Manafort, Stone and Kelly, for $600,000 last fall to press the "freedom fighter" cause in Congress and the White House. The coordinator for the UNITA account is Christopher M. Lehman, who until last fall was in the White House as a deputy to Robert C. McFarlane, then national security affairs adviser.