The settlers arrive here daily from eastern Brazil, lured by tales of land free for the asking and full of dreams and expectations. Along the dirt highway that slices across the territory of Rondonia, they plant small plots cut from the jungle and baptize their thatch-roofed mud huts with names like New Hope, Prosperity and New Life.

But the hundreds of thousands of poor Brazilian peasants who have poured into the western Amazon region since the beginning of the decade soon discover that life in the promised land is filled with unanticipated dangers. For many, the promise of a new and better life quickly turns into a nightmare of misery, suffering and violence.

Some find that the titles to the land they have bought, often with their last penny, are worthless and are expelled or even killed by capangas -- bands of gunmen in the pay of powerful ranchers. Others lose their entire families to disease, watch their crops rot for lack of a market or sit by helplessly as the seemingly fertile soil becomes desert.

Such problems have historically been the lot of pioneers. But elected officials, church leaders and technicians here charge that Brazil's Amazon pioneers are victims not so much of the frontier's inevitable ruggedness as the Brazilian government's lack of planning and the constant zig-zags in its Amazon development policy.

"The colonization of the Amazon has had both good and bad points," argued Dom Eurico Kreutler, bishop of the Xingu. "But without a doubt, the weakest point is the government's absolute lack of followup and support for the settler, which has caused immense and unnecessary suffering throughout the region."

"Settlers come here thinking they'll find El Dorado," said Agenor Martins de Carvalho, a lawyer who provides legal service for the poor in Porto Velho, 300 miles north of this frontier boom town. "Instead, they find complete chaos, cruelty and corruption."

Nowhere in the Amazon have the problems and pressures created by the influx of immigrants been felt more than in Rondonia, a Californiasized chunk of jungle 2,000 miles from Brazil's traditional population centers. From a meager 100,000 in 1970, Rondonia's population has increased sixfold, taxing to the breaking point government institutions and services which have not been allowed to keep pace with the territory's growth.

The settlement of Rondonia began in earnest in 1970, when Brazil's military rulers announced an ambitious "plan for national integration." A key section of this program spoke of settling as many as 5 million peasants on tracts of virgin Amazon soil by 1980, in what was envisioned as the most ambitious colonization effort since the opening of the American West a century ago.

The plan called for Brazil's National Land Reform and Colonization Institute to supply pioneer families with a small house, 250 acres of land, a modest grubstake and access to bank credit. The region's traditional isolation would be broken by the TransAmazon Highway, and settlers were to receive guaranteed prices for crops they raised.

But the failure of pilot colonization settlements along the TransAmazon and a change of government in 1974 has led to the abandonment of the integration program. An estimated 20,000 pioneer families in Rondonia alone have been stranded without hopes of receiving homesteads and thousands more have been left to fend for themselves without the guarantees originally promised.

Today, more than one quarter of Rondonia's population lives in what a government statistical report terms "a state of misery." Hospitals, schools and roads are in chronic shortage, and the territorial government is prohibited by law from hiring the hundreds of new police officers and agronomists it needs.

As an added heritage of the policy shift, dozens of precariously maintained settlements have sprung up along the dirt highway that serves as the teritory's only land link to the southeast. Boom towns such as Gi-Parana, Ariquemes, Pimenta Bueno and Colorado all have experienced periods in which growth has exceeded 100 percent a month.

But the largest of the new frontier towns is probably Cacoal, which has grown from five shacks and a cross-roads in 1972 to an estimated 65,000 today. Despite shortages of housing, water, electricity and, in the rainy season, food and medicine, families keep arriving.

Famous throughout the region for its rich volcanic soil, Cacoal is now producing bumper crops of coffee, cocoa, rice and corn. But the territorial growers' association expects that 40 percent of this year's yield will rot or spoil because of lack of local markets and the impassability of the highway during the six-month rainy season.

In the face of such difficulties, the Brazilian government is now taking steps to stem the tide of immigrants flowing into the western Amazon. New arrivals here report that officials at the highway post on the territorial border are now forcibly turning back would-be settlers.

In the southern states that supply Rondonia with the bulk of its immigrants, authoirites have posted warnings and distributed handbills intended to discourage farmworkers from taking the long trek. The notices are prominently displayed in bus stations and town squares where peasants are likely to gather.

"There are already thousands of families in Rondonia waiting for land," says one leaflet distributed in the interior of the prosperous farming state of Parana. "The majority of them have not even been able to register with the Land Reform Institute and thus cannot be sure that they will ever get land."

"The inability to adapt to the Amazon climate and the lack of adequate nourishment have generated serious problems," warns another. "The result has been the appearance of diseases such as malaria, gastroenteritis and verminosis among the migrant population."

But when the rainy season ends, nothing can stop the pioneers from coming, Caravans of cattle trucks pass daily on the highway here, each vehicle carrying three or four families and the few belongings they have brought with them: machetes, pots, pans, and a motley, scrawny assortment of goats, pigs, cows and chickens mingling with the human passengers.

The journey northward can involve up to two weeks of travel in rugged conditions. "You sleep under the truck at night, bathe in the creeks you cross and eat whatever you can find," says Jose Kaminski, 40, a father of five who recently arrived here with his family from the far south of Brazil after selling everything he owned to pay off his debts.

"I came because I just couldn't make a living anymore," explains Kaminski, an agricultural day laborer "Every year the big farms in the south use more machines and hire less people, and this year there was a really bad drought, so I thought I'd come up here and get a piece of land of my own."

Until that happens, though, Kaminski and thousands of migrants like him work for others, as they have done all their lives. For wages of as little as a dollar a day, they hire themselves out to foremen -- "cats" in the local slang -- who send them out to burn down the jungle on cattle ranches and cocoa plantations being set up by banks and businessmen from the southeast.

"Some of my clients have been waiting five, six, even seven years for titles to land the government promised them," says lawyer Carvalho. "One of them just lost four of his children to malaria in one week, and nearly all of them have been threatened with death at least once by 'cats' who didn't want to pay them for work they had done.

"Rondonia has become a land of absolute and total desperation," Carvalho adds. "The dream has ended, killed by reality, but there is no way for these people to turn back now."