Venezuelan President Luis Herrera Campins said yesterday that he urged President Reagan in talks this week to take "a clear stand" against right-wing political forces threatening the civilian-military government in El Salvador, and that Reagan had been "very receptive" to this request.

Herrera, whose country is the chief Latin American partner in U.S. support for Salvadoran President Jose Napoleon Duarte, indicated in an interview with Washington Post editors and reporters that the United States had neglected the threat of the extreme right in El Salvador in its concern over Cuban and Nicaraguan support for the country's left-wing guerrillas.

"There are sectors of the right-wing oligarchy that have been hard hit by the land reform" and nationalization of banking interests in El Salvador, "and would like the overthrow of the government," Herrera said. The United States should "take a clear stand so that this sector will not think the United States is giving it open or tacit support."

U.S. officials had no immediate comment on Herrera's account of his talks with Reagan or a possible stance against the Salvadoran extreme right. The Reagan administration has seen Venezuela as an important ally in its Latin American initiatives, however, and recently broke a long-standing U.S. policy by proposing to sell it 24 sophisticated F16 warplanes.

El Salvador's junta has been opposed since taking power in October 1979 by some members of the military and landowners who feel threatened by its takeovers of narrowly controlled private banks and its limited land-reform.

The agrarian program, designed to redistribute land concentrated in large holdings, has been plagued by right-wing terrorism, including several assassinations of local officials and would-be small holders. At the same time, right-wing political forces have been organizing under such leaders as Roberto d'Aubuisson, a former intelligence officer already exiled once for trying to overthrow the government, and have recently called for the immediate disbanding of the government.

While calling for a strong U.S. stand against these "regressive" forces during his talks with Reagan and Secretary of State Alexander M. Haig Jr., Herrera also argued against U.S. military initiatives aimed at Cuba or Nicaragua -- an option that Haig pointedly has refused to rule out in recent weeks.

"I made it clear that we were opposed to all armed intervention," Herrera said. "We should not sacrifice peace for security, because in the long run the peace would be lost" completely.

Venezuela has continued to support the Sandinista government in Nicaragua while criticizing the cutoff earlier this year of U.S. economic aid, and Herrera said yesterday that he believed that "the possibility for a democratic society in Nicaragua has not been exhausted."

The Venezuelan president, who established close ties to Duarte as a fellow Christian Democrat when Duarte was an exile in Venezuela during the 1970s, reiterated his support for the electoral process that the Reagan administration sees as a key to solving El Salvador's problems, saying it was "a beginning of a democratic and institutional solution."

Herrera stressed, however, that the electoral rights of the opponents of the government needed to be "guaranteed" by international supervision, and added that the Organization of American States could provide such supervision "if its members agree." In an address to the OAS yesterday, Herrera praised the regional organization -- which has not yet played a role in El Salvador -- and called for measures to strengthen it.