Washington — The Reagan administration is now fighting two uphill public-relations battles on major foreign policy fronts.
Both when it comes to Central America and to arms control negotiations with the Soviet Union, senior administration officials say they believe that their case is not being sufficiently heard.
They say that their information, propaganda, or public relations problem - call it what you will - is not just confined to the United States but extends to Western Europe as well.
In a breakfast meeting with reporters, Lawrence Eagleberger, undersecretary of state for political affairs, acknowledged in answer to questions that one can find little public support in Western Europe for America's policies in Central America. He said that there were a number of reasons for this: (1) an impression that the government of El Salvador is dominated by rightists; (2) reports reaching Europe of human rights violations carried out by that government; (3) the impression that the guerrillas fighting that government are ''agrarian reformers'' rather than communists; and (4) a feeling that negotiations with the guerrillas might produce the best outcome.
He also noted that socialists in Europe identify with some figures in the guerrillas' front movement, that many members of the Socialist International are opposed to US policies, and that El Salvador is an easy target for criticism which appeals to the left-wing factions of European socialist parties.
Mr. Eagleberger indicated that the administration's current campaign to publicize Nicaragua's military buildup and alleged Nicaraguan involvement in El Salvador was designed to overcome widespread skepticism about the administration's claims concerning Nicaragua. He said that an assertion made by US Rep. Michael Barnes (D) of Maryland that the administration was trying to generate a kind of ''war hysteria'' was ''baloney.''
Eagleberger said that the administration was at a public relations disadvantage because much of its information on Nicaraguan involvement in El Salvador came from sensitive intelligence sources. He said he hoped, but could not promise, that the administration would release more information on that involvement in future briefings.
When it came to arms control, Eagleberger indicated that the administration views with the utmost seriousness calls being made in this country and in Western Europe for a freeze on the deployment of new American and Soviet nuclear missiles. As Secretary of State Alexander M. Haig Jr. did earlier this week, Eagleberger argued that because the US was lagging behind the Soviet Union in a number of weapons categories, such a freeze would put the US at a disadvantage.
On March 10, 17 US senators and 115 members of the House of Representatives introduced resolutions in the Congress calling on the US and USSR to agree to such a freeze.
Eagleberger said a nuclear freeze would ''do serious damage'' to the US negotiating position at Geneva, where US and Soviet delegations are discussing possible reductions in nuclear weapons based in Europe. The US, he said, has thus far resisted Soviet proposals for a freeze which would, in effect, ''lock in'' Soviet superiority in medium-range missiles.
One way for the administration to escape from the pressures building up in both the US and Western Europe in favor of a freeze would be for the administration to open talks with the Soviets on strategic, or long-range, nuclear missiles. But the administration has indicated that the start of such SALT, or START, talks would depend on the general state of East-West relations, and that would obviously include developments in Poland. Eagleberger said the US expected ''soon'' to have ready START alternatives for President Reagan to consider before presenting them to the Soviets. But he also predicted a deteriorating situation this summer in Poland, a situation which would inevitably delay the start of START.