Encouraged by President Carter's opposition to legislation barring U.S. approval of multilateral loans to human-rights violators, Latin America's military governments are awaiting an indication of where the-administration's rights policy is headed.

At the same time, human-rights activists here are wondering if the Carter government is backing down on its initial strong rights stand.

Both groups are hoping, with similar apprehension, that Carter's Thursday speech to the Organization of American States, billed as a "substantive policy statement" on Latin America, will provide some answers.

Expressing the feelings of many Latin governments, Ecuador's Foreign Minister Jorge Salvador Lara said last week that his government hopes the United States will reconsider the "diverse" policies it has adopted in the area of human rights.

"We don't know if we've just seen the birth of Carter's rights policy," one official in Argentina's Foreign Ministry said, "or whether its climax has come and gone already."

From all initial euphoria during the administration's early days, human-rights activists in Latin America are now hoping, as one official said, that "Carter is just giving himself some room to maneuver" and not backing down.

The quesiton stem from a progression of events in the United States over the past month, beginning with the administration's reduction of military aid to Argentina, Uruguay and Ethiopia because of human-rights violations, and the conditioning of all such assistance, to all countries, on their human-rights situations. Argentina, Brazil, El Salvador, Guatemala and Uruguay, then such refused any military assistance under such conditions.

Last week, however, Assistant Secretary of State for Inter-American Affairs Terence A. Todman told a House appropriations subcommittee that substantial reduction of U.S. security assistance in Latin America was "inadvisable" because such an "abrupt attitude" could harm U.S. - Latin American relations.

According to one high air force official in Argentina's military government, this year's U.S. military assistance - amounting to a reduced $15 million that was turned down by his country - is "insignificant."

While many consider the military assistance go-round more politics than substance, the subject of multilateral bank loans is one that is much more important to Latin America. Nearly 70 per cent of all U.S. money distributed to the Third World last year went through multilateral channels and, as such, was not subject to direct congressional review.

Last year, Congress passed an amendment sponsored by Rep. Tom Harkin D-Iowa) ordering the U.S. representative at the Inter-American Development Bank to vote against most loans to countries with established records of human-rights violations. The United States voted against one loan to Chile on that basis, although the loan passed because the Latin nations voted for it.

Two weeks ago, the U.S. delegate voted in favor of a loan of Argentina only after voicing the administration's deep "concern" over that country's rights situation.

When an amendment extending the harkin concept to all multilateral institutions to which the United States contributes came up last week in the House of Representatives, however, Todman and State Department human rights coordinator Patricia Derian voiced the administration's opposition.

Subsequent House passage of the amendment brought editorial declarations from Latin America's often government-controlled press that the multilateral institutions should remain a political and pleas to turn the whole human-rights question over to the Organization of American States or the United Nations.

While the United States does not but itself, have a majority vote in the World Bank and other affiliated institutions, its impetus could spur other member countries, particularly the Scandanavians and Western Europeans, to vote against more loans.

In Argentina, more than $7 million in multilateral loans are already authorized for 1977.

"Without that money," the finance officials said, "we would be in serious trouble." Used for important development projects, "it is not only builds things, it provides jobs - 4,000 jobs alone in the Salta Grande dam project," one of the country's largest with external financing.

In addition, he maintained, the idea of approving loans to rights violators only when it is proven that the money will go to benefit a country's neediest people - an exception the Harkin amendment allows - is "against the whole philosophy of running a bank. The multilaterals are businesses, they are only interested in good investments.

Whatever Carter decides to do about human rights, the military government here will "never change its mind" about the way to fight internal subversion be leftist guerrillas, according to one high official.