The U.S. Information Agency said yesterday it will place the Worldnet international television network and Radio Marti and TV Marti under the Voice of America to create a powerful new government broadcasting unit within the agency.

The decision to consolidate the USIA's broadcasting divisions under a single head, Voice of America Director Richard W. Carlson, comes as the National Security Council completes its recommendations to the president on the government's broadcasting efforts, sources said.

The NSC has been studying whether there is a continuing need for the nation's separate radio and television stations broadcasting to Eastern Europe and the Soviet Union. The council is expected to recommend further study by a bipartisan commission, leading toward a future consolidation of

many radio broadcasting operations.

Two broadcasting networks -- Radio Free Europe and Radio Liberty -- operate under the Board for International Broadcasting, a separate organization.

USIA Director Bruce S. Gelb's decision to create one large unified broadcasting unit would give the USIA an advantage going into what is expected to be an executive branch turf war over who will absorb whom in any merger of broadcasting services, sources said.

Carlson said there will be some savings in administrative costs as a result of the consolidation, planned for October. Gelb promised employees yesterday that no one will be fired, since VOA and USIA's television operations have "shortages of people to do the job."

Carlson said he welcomed the move because "the VOA's reputation for honesty and accuracy and its pervasive name identification will benefit television as it expands."

The VOA has about 3,000 people and a budget of $171 million to broadcast in 42 foreign languages and English. Worldnet television has about 340 employees and a budget of $31 million. Radio and TV Marti have a budget of some $20 million and about 160 employees.

The consolidation is a major victory for Carlson, whom Gelb attempted to fire in February. Gelb told VOA employees yesterday there was "no one he had more respect for than your leader, Dick Carlson."

The consolidation is expected to reduce the rivalry between radio and television that has plagued USIA for some time. The competition between the broadcasting divisions recently surfaced in Poland when Stephen Murphy, who heads the Office of Television and Film Service, complained to the Polish cabinet minister in charge of broadcasting about the location of a satellite dish donated by an American company at a Polish radio, rather than a television, station, according to a source.

Murphy could not be reached for comment last night.

A U.S. Embassy official in Poland, in a widely circulated memo, called the Murphy letter a "needless and potentially harmful gaffe" that was really a dispute between two elements of the USIA.

Sources on Capitol Hill and in the executive branch said that the consolidation had long been urged by several members of Congress.