SAN JOSE, COSTA RICA, JAN. 29 -- Nicaraguan government and rebel negotiating teams, concluding their first face-to-face talks in their six-year-old civil war, today agreed to meet again next month but made no apparent progress on setting the terms of a cease-fire.

"There was what we could call a verbal cease-fire," said Nicaraguan Bishop Bosco Vivas, who served as mediator for the two days of talks at a Roman Catholic seminary here. Citing an informal agreement by both sides to tone down their rhetoric, Vivas called today's meeting "very positive" and said he found "good will on both sides to seek a cease-fire in Nicaragua" in the near future.

He said the two sides agreed to meet Feb. 10-12 in Guatemala, subject to confirmation by Nicaragua's Roman Catholic primate, Cardinal Miguel Obando y Bravo, the chief mediator in the negotiating process.

In separate news conferences after Vivas' announcement, each side expressed a desire not to create obstacles for future talks and avoided harsh denunciations of the other's radically different cease-fire proposals. Each also made an appeal regarding the issue that has overshadowed the talks: an imminent vote in the U.S. Congress on additional funding for the rebels, known as contras.

Nicaraguan Vice Foreign Minister Victor Hugo Tinoco, the head of the Sandinista negotiating team, urged Congress to defeat a Reagan administration request for $36 million in new funding for the contras, or risk seeing the peace process break down.

"It is our hope that in the next days the important decisions that American society has to take will not destroy all these efforts," Tinoco said. "We hope they will not throw more fuel on the fire of war."

The head of the contra negotiating delegation, Nicaraguan banker Jaime Morales, said that "the resistance has learned to live with or without aid" and that his side was negotiating not in the hope that aid would pass, but to achieve peace.

Later, contra director Pedro Joaquin Chamorro, who did not take part in the talks, said in an interview that the Sandinistas had reversed their long-standing refusal to negotiate directly with the contras as a result of the U.S. aid. "This never would have happened if not for the military pressure" that contra aid has put on the Sandinistas, he said.

"If the aid is not approved, then the negotiations would stop and the Sandinistas would win," Chamorro said. "The Sandinistas wouldn't have any incentive to negotiate."

Chamorro's sister, Claudia, the Nicaraguan ambassador to Costa Rica, participated in the talks as part of the Sandinista delegation.

In a separate development, Fernando (El Negro) Chamorro, a former contra commander who is no relation to Pedro Joaquin Chamorro, flew back to Managua today to join the internal opposition to the Sandinistas. He told reporters before his departure that he had accepted a government amnesty in December.

Fernando Chamorro, who gave up the leadership of a small faction allied with the main contra force more than a year ago, said he still respects the contras, but believes that both sides should stop fighting.

In the Sandinista news conference after today's five-hour talks, Tinoco obliquely criticized the rebels' cease-fire proposal as containing elements outside the framework of a Central American peace accord signed last August. He referred to the contras' demands for sweeping political changes in conjunction with a cease-fire agreement to assure "democratization" in Nicaragua.

Tinoco insisted that political subjects had not been broached during the discussions, but the contras gave a somewhat different account.

Contra officials said their position had been buttressed by a letter that the mediating team had received from the Nicaraguan Democratic Coordinator, an unarmed internal opposition group. They said the letter, given to both sides, called for a new "national dialogue" involving all the Nicaraguan actors in the country's conflict.

Morales, the chief contra negotiator, said his delegation had touched on political matters in repeating a contra demand that a cease-fire become "an integral part of a political-military negotiation" among the Sandinistas, the contras and the internal civic opposition in Nicaragua. But he said the contras had refrained from pressing a discussion of the political subjects in detail to avoid an immediate breakdown of the dialogue.

In an interview after today's talks, contra negotiator Walter Calderon, a 32-year-old field commander who uses the alias Tono, called the Sandinista cease-fire proposal a modified demand for the contras' "unconditional surrender." He noted that while a previous Sandinista proposal called for the contras to lay down their arms at the beginning of a cease-fire, the latest document gives them 30 days to keep their weapons and ammunition.

Paul Reichler, an American lawyer who serves as an adviser to the Sandinista delegation, said, "Each side has to abandon hope of an ultimate military victory. They have to accept that this is going to be resolved politically, not militarily." He said the Sandinistas have accepted that premise and that he hoped the contras would, too.