Even as its economic ministers prepare another dose of harsh austerity measures, the Brazilian government is facing growing pressure from businessmen, the press and its own officials to abandon the wobbling financing scheme for its huge foreign debt.

The austerity measures represent the government's response to Brazil's failure to meet the targets of the financial rescue plan hastily arranged last year with the International Monetary Fund and U.S. and other international banks.

Largely because of overruns in government spending, the IMF and banks have withheld some $950 million in loans due to be given to Brazil this week, aggravating the country's already severe shortage of cash.

The government hopes that new austerity measures--including higher food and fuel prices and drastic cuts in state spending--would persuade the IMF next month to release the delayed loans and perhaps to modify some of the stringent economies required of Brazil, officials and diplomats say.

But spending cuts and higher prices would only deepen Brazil's painful recession. Rather than face that, a growing coalition of industrialists and political and government officials is calling for a large-scale renegotiation of the foreign debt.

Though the more drastic solutions are largely supported only by small leftist and nationalist groups, the idea of renegotiation has recently been accepted by major business and industrial organizations, several of Brazil's leading newspapers and members of the government's political party, including a prominent senator, a state governor and a cabinet minister.

"If we were a rich and developed country, we could say we are going to create a nice recession to clean house," Helio Beltrao, the federal social welfare minister, told reporters last week. "But unfortunately, the social problems are such that we can't play with recession."

Political analysts and diplomats here say that neither the military backed government of President Joao Figueiredo or the banks holding Brazil's $83 billion foreign debt are soon likely to accept the possibility of a renegotiation involving substantial delays of payments by Brazil.

However, these sources say that the internal pressures are likely to toughen Brazil's pressures in future loan talks.

Some experts here predict that, caught between shrinking loan commitments from banks and the rising internal costs of recessionary measures, the government will eventually have no choice but to seek a major debt restructuring. "Something will have to change," said Robert Blocher, an investment analyst and former president of the Chase Manhattan Bank Subsidiary in Brazil. "The government will respond when there's no more money around. This will have to be studied from a totally different light."

The debate over the debt comes at a time when Brazil's military administration is more vulnerable to internal political pressure than ever before in its 19 year rule. Elections allowed by the military last year brought opposition leaders to power in the country's richest and most populous states, and government leaders have faced increasing economic demands from the business and conservative political sectors that back the government's Social Democratic Party (PDS).

Figueiredo, who has led the military's slow transition toward democratic government since 1979, is now immersed in the delicate exercise of coordinating the selection of Brazil's next president, due to take office in early 1985.

Some government supporters have begun to warn that the political repercussions of Brazil's IMF-backed austerity measures could derail the process of consensus building involved in the presidential nomination--and with it, Brazil's political stability.

Brazil is in a "state of pre-social convulsion," Roberto Magalhaes, the PDS governor of the northern state of Pernambuco, was quoted as telling reporters last week. "Without social stability there will be no presidential succession in 1985," he added.

And central bank President Carlos Langoni, who leads Brazil's negotiations with the IMF, said Brazil's adjustment program so far has been "socially perverse and economically inefficient."

It is the social consequences of economic stagnation that have most fueled opposition to new austerity measures. Despite dynamic growth in the last two decades, much of Brazil's population of 120 million remains poor and malnourished, and huge ghettoes surround its major industrial cities.

After two years of recession, government figures show there are some 400,000 unemployed workers in the key industrial center of Sao Paulo, where two days of rioting by poor workers erupted last month. The riots led many political leaders to conclude that further reductions in jobs and living standards could create unmanageable social unrest.

"People are losing their standards of living, and they are angry and desperate," said Raphael de Alimeda Magalhaes, an economist and leader in the Brazilian Democratic Movement, the largest opposition party. "They are looking for a miracle, a savior for the country. You can see populism, nationalism and authoritarianism starting to grow."

Following the failure of the government to meet spending and inflation guidelines in the first four months of this year, many Brazilian businessmen and economists have also begun to argue that the program negotiated with the banks and the IMF was too modest and that some of its measures are contradictory.

To increase exports, for example, government officials ordered a 30 percent devaluation of the Brazilian cruzeiro in February, in addition to the regular practice of small "minidevaluations." The move helped to boost the county's trade surplus to record levels in March and April, but spurred inflation to an annual rate of more than 130 percent.

The measure also helped to increase the overspending of state companies, whose budgets include large interest payments on dollar loans that soared in relative value with the devaluation.

Over a longer term, economists here are arguing, cuts in state investments and heavy emphasis on exports at the cost of other sectors will damage Brazil's existing base and make future repayments even more difficult.

"You are driving the economy to the breaking point, spending all the energies of the country on this very short term purpose," said Edmar Bacha, a professor of the Catholic University in Rio de Janeiro. "There are a lot of politics for the short term that are bad in the long term.

"We need a breathing space," Bacha added. "We cannot go on living day to day with the only worry being how to close the accounts at the Banco do Brasil in New York at 6:00 p.m."

But as the country awaits the new austerity measures, most analysts believe that the debate over how to handle the debt burden is only beginning to heat up. "They are complaining now that the program is too tough," a diplomat said. "But they haven't yet gotten to work on it. And it may be they will really have to push the economy through a ringer."