Secretary of State Alexander M. Haig Jr., in the administration's most extensive top-level statement of its East-West policies, said yesterday that the United States is prepared to improve relations with Moscow in return for "greater Soviet restraint and greater Soviet reciprocity."

Described in advance by the State Department as a major pronouncement, Haig's address to the American Bar Association in New Orleans was a restatement of nearly every aspect of the administration's initial policies toward the Soviet Union. It also sought to answer some criticisms of those policies and where they may lead.

State Department officials described the speech as a road map for about the next six months of Soviet-American interaction, including Haig's planned meeting at the United Nations next month with Soviet Foreign Minister Andrei Gromyko. One official described the speech as a harbinger of a "more balanced" approach to Moscow that holds out at least some incentives for cooperation.

Much of the speech was in a stern, accusatory tone, such as the warning that "the Soviet Union must understand that it cannot succeed in dominating the world through aggression." At the same time, Haig said the United States is offering "a broader relationship of mutual benefit" if Soviet policies change.

"President Reagan has written President Leonid Brezhnev that we want a constructive and mutually beneficial relationship with the Soviet Union," Haig reported.

He said Washington offers Moscow, in return for shifts in existing Soviet policies, "a reduction in the tensions that are so costly to both our societies . . . diplomatic alternatives to the pursuit of violent change. . . fair and balanced agreements on arms control . . . the possibility of western trade and technology."

In the absence of Soviet restraint, Haig added, "our military capability, our alliances and our friendships will enable us to protect our interests."

Apparently responding to charges that U.S.-Soviet communications have languished in a period of sharply increasing tension, Haig said the administration's message "has been reinforced by over 50 direct contacts with senior Soviet diplomats" in the last six months.

Haig sketched in broad strokes what he called "a concrete agenda" in three areas:

Geopolitical issues arising from "Soviet intervention in regional conflicts," especially in Afghanistan and Cambodia.

Haig commended the European Community proposal, recently rejected by Moscow, for a two-stage international conference on Afghanistan. Instead of accepting this, he charged, the Soviets prefer to promote the "bizarre theme" that the United States is "the source of the trouble" and is unwilling to negotiate.

"The Soviet Union must begin to understand that Afghan resistance and international pressure will be sustained," Haig declared.

Similarly, he said, in Cambodia the Soviets and "their surrogate," Vietnam, face a choice: "international isolation and failure, or international cooperation and the way out." He criticized Moscow and Hanoi for not attending the recent United Nations-sponsored conference on Cambodia.

Arms control, specifically "balanced and verifiable agreements that establish true parity at reduced levels."

The objective of the proposed talks on theater nuclear forces in Europe, which the administration has agreed to undertake at the urging of Western European allies, was described by Haig as "equal, verifiable limits at the lowest possible level of U.S. and Soviet long-range theater nuclear weapons."

Haig said the administration has initiated "intense preparations and conceptual studies" toward a resumption of SALT talks on strategic nuclear weaponry, but he gave no timetable or further detail.

Economic relations, which "have grown rapidly" over the last decade but "have not restrained the Soviet use of force."

"The time has come to refashion East-West economic relations," Haig declared, saying without elaboration that the United States seeks "to expand those ties that strengthen peace and serve the true interests of both sides."

He also said the Soviets, who have looked to Western agriculture, technology, trade and finance to relieve problems in their bloc, "cannot have full and normal economic relations if they are not prepared to respect international norms of behavior."

Haig called for efforts "to constrain Soviet economic leverage over the West" and said that "above all, we should not allow the transfer of western technology that increases Soviet war-making capabilities."