A House subcommittee dominated by critics of administration policy in Central America yesterday approved a $1.39 billion regional foreign-aid package that Republicans acknowledged could form the basis for a bipartisan agreement.

The measure conditions aid to El Salvador and Guatemala on presidential certification of progress in human rights and bans it in case of a military coup, but administration officials voiced no objection.

Republicans indicated they would resist a section, approved last year by the House, that bans use of U.S. armed forces "into or over El Salvador or Nicaragua for combat" without a declaration of war.

They also promised more opposition to a resolution banning aid to Chile until the president certifies that human rights are being observed.

Rep. Michael D. Barnes (D-Md.), chairman of the Foreign Affairs subcommittee on Western Hemisphere affairs, acknowledged after the 4-to-3 party-line vote approving the bill that he has "a different strategy this year."

Last year's subcommittee measure, laced with tough conditions on aid packages to El Salvador, lost on the House floor to a Republican substitute package.

This time, Barnes deftly gutted potentially incendiary amendments by members of both parties and later noted with satisfaction that no one had tried to alter his proposed aid figures, only the political language surrounding them.

"I started out with a bill I think can pass, and I'm trying to hold the bill together," he said. "So far, so good."

The measure, $292 million less than the administration had requested, would provide the same $1.39 billion in economic and military aid to Latin America and the Caribbean for fiscal 1986 that Congress provided in its continuing appropriations resolution for fiscal 1985, in accord with wide congressional efforts toward a spending freeze.

It shifts some funds from El Salvador, Honduras, Costa Rica and two regional facilities to provide sharp increases in economic aid to Bolivia, Ecuador and Peru.

Aid to El Salvador would be cut substantially from the administration's request for $350.6 million in economic aid and $132.6 million in military aid to $264.7 million and $113.2 million, respectively, for a $377.9 million total.

An amendment from Rep. Gerry E. Studds (D-Mass.) requiring that El Salvador observe "applicable rules of international law" regarding civilians in bombing target areas passed despite objections from Rep. Henry J. Hyde (R-Ill.) that it was "an invitation to mischief" on the part of leftist Salvadoran guerrillas.

Deputy Assistant Secretary of State James H. Michel opposed an amendment from Rep. Samuel Gejdenson (D-Conn.) requiring certification of progress in the probe of murders of at least 18 peasants last year in the town of Las Hojas.

"To the extent that Congress imposes these things when they are already the policy of the Salvadoran government, you detract from the accomplishments of that government," Michel said.

Aid to Honduras, which has requested substantial increases, would drop from the administration's overall $230 million request to $170.2 million, and Costa Rica would receive $166.6 million instead of the $190 million sought by the administration.

In related action, the Senate detached $175 million in emergency non-food aid for Africa from its entanglement with proposed U.S. farm-relief measures and passed it on a voice vote. Another $700 million in food assistance is pending