Brazil's increasingly violent dispute over agrarian reform, which cost about 320 lives last year, has forced the hand of President Jose Sarney.

During a visit next week to the Amazonian backlands where some of the most deadly battles have occurred, Sarney is scheduled to announce a sweeping governmental effort to resolve conflicts over Brazil's most abundant natural resource, land.

The president and Justice Minister Paulo Brossard already have announced that the government will dispatch civil, federal, and military police with orders to confiscate arms from landlords and peasants and to end the "atmosphere of impunity" that reigns in much of the countryside.

This campaign is intended not only to end the violence but to put all of Brasilia's muscle behind the Sarney government's own beleaguered program for agrarian reform.

During the past 15 months, the controversy has turned into the most explosive issue before the fledgling civilian government. It is criticized by the right and left, by clergy and laity, and by small landholders and big estate owners.

The influential Roman Catholic Church has branded the government's plan too timid, while large property-holders have termed it "communist." As the debate has grown more shrill, the government has appeared virtually paralyzed.

The church has documented the 320 deaths in land conflicts last year. This year's death toll is increasing by about 20 per month, with advocates of the reform laying much of the killing to organized land owners.

While much of Brazil is virtually uninhabited, the amount of productive farmland is limited and its ownership highly concentrated. Schemes for colonization of endless tracts in the Amazon Basin have triggered conflicts in the few areas of truly arable land.

Sarney promised the agrarian reform a year ago, but it took until October for the government to approve a plan involving redistribution of untilled holdings. And only last month, after the murders of an activist priest and a land settlement agent, were the regional programs signed into law. The delay has been costly.

Frustrated by the lack of progress and increasingly isolated within the Sarney government, land reform minister Nelson Ribeiro resigned last week. During his tenure, few properties had been expropriated, and those that were taken provoked a backlash by influential landowners.

Despite the bloodshed, land reform still existed only on paper. Ribeiro increasingly faced dissent inside and outside his own ministry. A Cabinet minister closer to Sarney bypassed Ribeiro and handed the president a rival -- and blander -- reform plan.

Ribeiro was replaced by Dante de Oliveira, 34, a city mayor who became popular for his 1984 bill in congress to restore popular elections for president. Oliveira, a one-time member of a leftist guerrilla group, has solid credentials with the Brazilian left. But his nomination did not quiet land reform's most vocal advocates, the powerful Brazilian Bishops' Conference, which strongly backed Ribeiro. His departure, said the president of the conference, Archbishop Ivo Lorscheiter, "could aggravate violence in the countryside."

In late May, the daily Jornal do Brasil published a story saying Justice Minister Brossard had complained to Sarney that the church was "organizing invasions" of land by squatters.

Brossard emphatically denied the reports, but later, on a nationwide television program, charged that although "the church as a whole cannot be blamed . . . , there are priests who are creating difficulties for agrarian reform."