A document classified by the Central Intelligence Agency and characterized by the Reagan administration as evidence that the Nicaraguan government has an elaborate plan to manipulate the U.S. Congress and media, is based in part on a New York firm's 43-page report that proposes a routine lobbying strategy, according to administration sources.

The consultants' lobbying plan, written in January by two former Roman Catholic priests working for a firm called Agendas International Inc., proposes a media and public relations strategy for the Nicaraguan government to counter Reagan administration attempts to win congressional approval of military aid for rebels fighting the Sandinista government. President Reagan this week asked Congress for a package including $70 million in military aid and $30 million in humanitarian assistance.

Employing language and tactics similar to those of many other legislative lobbying campaigns, the consultants' report stresses the importance of "choosing the right symbol or image" and advocates targeting key congressional districts "with op-ed pieces, solidarity activities and, most importantly, religious group activities."

The classified CIA document, which sources said includes considerable information from the consultants' report, has been an object of controversy for more than a week since CIA Director William J. Casey distributed copies at two White House meetings with more than 60 members of Congress. White House spokesman Larry Speakes described the Nicaraguan effort detailed in the document as a "highly sophisticated public relations and disinformation campaign."

Casey's attempt to dramatize the administration's uphill campaign of supporting the rebels, also known as contras, against the Sandinistas backfired on Capitol Hill.

Sen. David F. Durenberger (R-Minn.), chairman of the Select Committee on Intelligence, called the maneuver an "outrageous" attempt "to portray every senator and congressman who votes against lethal aid as a stooge of communism."

White House officials, stung by the criticism, said that a declassified version of the CIA document would be made public. However, senior administration officials said yesterday that the CIA document would not be released because of agency fears that sensitive sources and methods could be compromised. White House and State Department officials advocated releasing the document.

"We managed to shift the focus from the importance of aiding the freedom fighters to the rather dubious tactics we were using to convince Congress," one White House official acknowledged yesterday.

The consultants' report was obtained by The Washington Post from a source close to the Nicaraguan government. Entitled "Strategic Analysis/Planning for 1st Quarter of 1986," it was prepared by Agendas International, a small New York-based public affairs and consulting firm headed by Darryl Hunt and Donald Casey, two former Maryknoll priests.

The firm, which is registered with the Justice Department as an agent of the Nicaraguan government, is paid about $25,000 a month as part of a long-term contract with the Sandinistas, Hunt said yesterday in a telephone interview. The firm spent several weeks preparing the report, he added.

Much of the consultants' report suggests standard lobbying tactics and common sense. For example, a section on "Targeting Congressional Districts" begins with the observation that "there still exists in Congress considerable opposition to providing lethal aid to the contras."

The "core of opposition to military aid to the contras" is sur- rounded by a "larger, fluid group of moderates who can be swayed one way or the other" and should be the targets of Nicaragua's congressional district campaign, the consultants observe.

The analysis and strategy in this section and many others summarize information obtained from newspapers. For example, it says, Sen. Arlen Specter (R-Pa.), "who voted against contra aid, is running for reelection in Pennsylvania."

The report advocates concentrating on the major media markets of New York, Chicago, Washington and Los Angeles and the secondary market of Nashville, which "is the principal media center for the congressional districts of all three Tennessee Democrats who switched their votes" to favor contra aid in 1985.

The consultants' report also strongly urges that the Nicaraguan government publicly issue a "one-sentence denial" of charges of human rights violations by Alvardo Baldizon, a former deputy interior minister who defected to the United States last year. Such a denial "must be stated so that it can be included in press reports and human rights reports."

According to seven pages of "recommendations for action," the document calls for Carlos Tunnermann Bernheim, the Nicaraguan ambassador to the United States, and United Nations Ambassador Nora Astorga to "engage themselves with the U.S. media a great deal over the next several months . . . . Astorga should not only meet with The New York Times, but with the progressive press and television people as well."

"We suggest that the govern- ment consider lifting prior restraint on all media" in Nicaragua, the consultants' report says, noting that government rules give the Sandinista government a particularly bad image in the United States. "Instead of prior restraint, we suggest that the government formulate detailed regulations for the media and fine those who violate the regulations."

The document places great emphasis on getting editorial opinion pieces in the U.S. media and lists 17 themes that might be used, including "Blueprint for Disaster: U.S. Policy Ignores Realities" and "Why the Contras Can't Win."

"I would call it an information plan . . . corporations, governments all do this kind of analysis," Hunt said.

"We don't buy or receive free time on American television . . . . We are just attempting to recommend how the Nicaraguan government get its story out," he said.