QUILALI, NICARAGUA, OCT. 7 -- A unilateral government cease-fire began today in parts of three war-torn provinces, and in this northern village the start of the truce nearby sparked a rare freewheeling exchange of views between Sandinista authorities and residents disgruntled with some of their policies.

In Quilali, 175 miles northeast of the capital on the edge of a 215-square-mile cease-fire zone, peasants with tears and trembling voices openly expressed their yearning for an end to the six-year-old war as well as their doubts about the Sandinista government's sincerity in seeking peace.

The government took the first steps yesterday to create cease-fire zones it announced Sept. 22 by pulling its regular troops back from the designated mountain areas and posting them around the zones' perimeters. By yesterday afternoon about 500 Sandinista troops had trudged out of the zone near here, parking their howitzers along the roads with plastic bags over the muzzles.

The leftist government established this zone, and others in Jinotega province in the north and Zelaya in the south, to speed its compliance with a regional peace plan signed Aug. 7 in Guatemala by the five Central American presidents.

Bosco Matamoros, a spokesman for the U.S.-backed rebels, known as counterrevolutionaries or contras, rejected the cease-fire as "absurd" and "made to impress the U.S. Congress" in a telephone interview from Washington. President Reagan has said he will ask Congress to approve $270 million in new aid to the contras. The contras demand direct talks between their leaders and the government to reach a negotiated cease-fire.

The rebels' top military commander, Enrique Bermudez, has been heard here every night recently over the contras' AM station, Radio Liberacion, ordering his troops to ignore the cease-fire and warning visitors to the zone that they risk being caught in combat or captured.

In meetings in schools, churches and Red Cross centers around the cease-fire zone, church-run peace commissions made up of prominent local residents with a broad range of political views have been explaining the cease-fire. Its purpose, they said, is to allow families wtih members fighting with the contras to contact their rebel relatives inside the cease-fire zones to urge them to accept a government amnesty and return to civilian life.

The government estimates that about 200 contras operate in the zone north of Quilali, and many more peasants in these hills have relatives fighting with the contras elsewhere in Nicaragua.

On Monday, contras ambushed a transport truck on a road near Quilali, killing six civilians including a 2-year-old child, residents said. Also Monday, a skirmish erupted between Sandinista Army regulars and a contra patrol that crossed their path in a hamlet named Manchones.

Today in Manchones, in the heart of the Quilali cease-fire zone, calm reigned and reporters found Pilar Torres praying for peace as her infant daughter chewed on an empty rifle shell. The contras had retreated into the surrounding hills.

Independent reports from the other two zones indicated there was no fighting in them today.

Peasants on horseback and driving oxen teams stopped eagerly to talk to reporters along the rock-strewn road. They were looking for a sign of good will from the Sandinista government before starting to call on friends and relatives to come down from the hills and turn in their guns.

"You won't find any direct faith in the Sandinistas out here," said farmer Reynaldo Meza. "The people are still afraid to talk openly with their contra relatives because they think reprisals from the government will come soon after."

At least 40 peasants from these hamlets are serving time in Sandinista jails on suspicion of collaborating with the contras, residents said. They said many peasants do not want to fight with one side or the other, but will not refuse food to any passing visitor.

In the town of Quilali, residents poured out their fears about the cease-fire in a meeting last night with members of a regional peace commission, including Carlos Manuel Morales, the Sandinista equivalent of a provincial governor.

"We are not going to revive our dead. But we hope the cease-fire will help everyone comply with the Guatemala accords, so we will spare ourselves more death and pain," Morales said.

But resident Isidora Salgado stood up boldly, her eyes welling with tears, to say she did not want to serve on a peace commission in her hamlet. She said two of her brothers died fighting for the Sandinistas in their 1979 revolution, and five now are contras. Salgado said she was imprisoned for a week in 1985 for interrogation about her brothers and her family has been watched and harassed.

"What will I tell my brothers if they ask me if it's really safe for them to come home?" she asked.

Another resident, Idalia Vilchez, said she is willing to walk out into the cease-fire zone to send a message to her 18-year-old contra fighter son, Jimmy, to see if he is ready to come home. But she reminded Morales that she had been jailed three times in recent years because her son is a contra.

"I can't see that the government is doing a very good job yet carrying out the peace accord," Vilchez lectured Morales.

Morales did not give the villagers much hope about their prisoners, saying their release under a peace-plan amnesty would occur only if the U.S. Congress votes down new aid for the contras.