Fears of further leftist guerrilla takeovers in Central America as a result of the Nicaraguan revolution have triggered a major debate within the Carter administration about whether the United States should resume military aid to the rightist regimes in El Salvador and Guatemala.

Reliable sources said yesterday that at a recent high-level White House meeting, representatives of the Defense Department and the intelligence community argued strongly that both countries, but particularly El Salvador, are in imminent danger of increased, Cuba-assisted guerrilla warfare.

The spokesman for the Pentagon and the intelligence agencies contend that the United States should help the armed forces in El Salvador and Guatemala to counter the threat by resuming the former U.S. role as their principal supplier of arms and training.

The sources said that, largely because of objections from the State Department, it was decided not to pursue the idea now. But, the sources stressed, although the military aid proposal is in abeyance, it still is under consideration as a policy option and is scheduled for another White House review.

The main thrust of current administration policy is to seek friendly relations with the Sandinista-dominated government in Nicaragua. But, the sources said, Defense Department and Central Intelligence Agency officials remain concerned that Cuba will use the monemtum generated by the Sandinista victory in Nicaragua to try and breathe new vigor into the guerrilla movements stirring in El Salvador, Guatemala and Honduras.

El Salvador and Guatemala are among a group of military-dominated Latin American Countries that two years ago rejected U.S. military assistance on the grounds that Washington's pressures over huuman-rights questions were an interference in their internal affairs.

More recently, fears about the spill-over effects from the Nicaraguan civil war have caused both countries to inquire about reestablishing the old ties that saw them receive from the United States almost all of their military training and sizable credits for the purchase of military equipment. But efforts to move in that direction have been blocked by liberals in Congress.

The sources said U.S. military and intelligence officials are most immediately concerned about the situation in El Salvador, where a long period of civil war between President Carlos Humberto Romero's government and leftist terrorists recently erupted into widespread rioting and killing.

According to the sources, one result of the White House meeting was that Viron P. Vaky, assistant secretary of state for inter-American affairs, was sent last week on an unpublicized visit to assess the situation in El Salvador. Although Vaky visited several countries in the area, the sources described his stopover in El Salvador as the most important part of his mission.

Vaky is understood to have concluded that the situation there is rapidly becoming a carbon copy of what happened in Nicaragua -- that the polarization between the ultra-rightist Romero government and its opponents is becoming so intense as to make unlikely a moderate solution involving middle-road forces acceptable to both sides.

Yet, the sources said, Vaky who has great influence with Secretary of State Cyrus R. Vance, is understood to be among those cautioning against a jump back into close U.S. ties with the Saladorean and Guatemalan armed forces.

Although some State Department officials are known to advoate a more hard-line approach, the department's basic position is that such a move could undermine the effort to gain the confidence of the Sandinistas in Nicaragua, create suspicion and hostility among Latin America's democratic governments and provoke fierce new opposition from congressional liberals.

In addition, the sources said, Vaky and other ranking State Department officials are understood to have argued that renewed military aid should be extended to El Salvador and the Guatemalan regime headed by Gen. Romeo Lucas only in exchange for efforts to disarm the tensions in their countries by easing up on repression and denial of political rights.

However, according to the sources Vaky, on the basis of his trip last week, came away the the impression that the Romeo government is suffering from a "siege mentality" and is unwilling to make any concessions toward liberalization.

On the other side, the sources said, the dominant view in the Pentagon and the CIA is that the risk of Nicaragua becoming a Cuban satellite and a springboard for exporting revolution throughout Central America is too great to be ignored.

As a result, the sources added, powerful forces in these agencies are arguing that the administration should hedge its hopes for good relations with the Sandinistas by moving to prevent the Nicaragua experience from being repeated in the other countries -- even if that means reverting to the discard policy of close U.S. ties with rightist military regimes.