The Sandinista government, trying to improve relations with Indians inhabiting Nicaragua's Caribbean coast, has pledged to grant some degree of self-rule to the region and has opened formal talks with one of the two major Indian guerrilla groups.

The government named a nine-member commission on Dec. 5 to design laws and policies to guarantee some autonomy in the coastal zone inhabited by Miskito, Sumu and Rama Indians.

"The central government is going to be modified, to be reorganized in that region, beginning with the recognition of a different reality -- historical, cultural, linguistic and social," the commission's coordinator, Deputy Interior Minister Luis Carrion, said in an interview yesterday.

While the government did not spell out any ideas in advance on how much autonomy would be granted, the naming of the commission appeared designed to satisfy the Indians' desire for self-rule and help end the insurrections by the two Indian guerrilla groups. The government has drawn international criticism for its treatment of the Miskitos since the 1979 revolution, and particularly for the forced resettlement of thousands of Miskitos in early 1982.

Carrion met for two days last weekend in Bogota, Colombia, with Brooklyn Rivera, leader of the Indian rebel organization Misurasata. Rivera, who visited Managua in a peace bid in October, is the first prominent Nicaraguan rebel leader to hold formal talks with the government.

The sides agreed to meet again on Jan. 19-20, but both negotiators said that they had disagreed over fundamental issues and accused each other of intransigence. Disputes arose over whether the Indians have sovereign rights and which side should develop the autonomy plan, the two negotiators said.

"It's good that the government has a commission to study autonomy, but it cannot be accepted that the conflict is going to be resolved within this framework," Rivera said yesterday by telephone from his home in San Jose, Costa Rica.

Misurasata guerrillas under Rivera's leadership have fought the Army along the southeastern border with Costa Rica since 1982. Fighting has dropped off considerably in recent months, however, and during the talks the government proposed a cease-fire.

Rivera said he resisted this and pressed demands that the government formally recognize that the three indigenous tribes were "sovereign peoples." He also asserted that "any project [for autonomy] must come from us" rather than from the government.

"There was difficulty with the government's position on recognizing the indigenous as peoples. This recognition is essential," Rivera said.

Carrion, a member of the Sandinista Front's nine-man directorate, said that to recognize the Indians as sovereign peoples would risk granting what he called a "base" for them to seek to establish an independent nation. While Misurasata seemed willing to accept autonomy within Nicaragua, Rivera appeared to keep open the possibility of seeking to establish a separate country.

"It is inconceivable that a revolutionary government cannot recognize these indigenous peoples as peoples when in other countries Indians are recognized as nations," Rivera said.

Carrion said the government would consult with Misurasata -- but also with other Indian organizations, including the pro-Sandinista group Misatan -- in preparing its autonomy plan. "Misurasata cannot speak in the name of all of the Indians of Nicaragua," Carrion said, although it includes members of the three groupings. He also said that the government had to consider the situations of non-Indian people in the coastal zone, including those of African, Asian and European descent.

Misurasata formally belongs to the insurgent Democratic Revolutionary Alliance, which includes former Sandinista hero Eden Pastora. The other major Indian insurgent group, Misura, is linked to the Honduran-based Nicaraguan Democratic Force. Carrion expressed doubt that Misura, headed by Steadman Fagoth, would come to the bargaining table.

"Fagoth has placed his bets with the counterrevolution," Carrion said. He said that Rivera only had between 400 and 500 men under arms, compared with at least 6,000 in the Nicaraguan Democratic Force, so a cease-fire with Misurasata alone would "not change the balance of forces in the war." Rivera suggested that he had more than 500 men.

Only river and air traffic connects the sparsely populated Caribbean coast to Nicaragua's population centers along the western Pacific coast and central mountain range.