South Africa's once-apolitical business community has been transformed into its most vigorous political lobby by the racial and economic crisis that has hit the country during the past 16 months.

Businessmen who once thought it imprudent, even beneath their dignity, to venture into the controversy surrounding apartheid -- and whom some suspected of secretly admiring a system that kept black radicalism in its place -- have become what one business leader recently called "born-again liberals."

Scarcely a day passes without some prominent businessman joining the corporate chorus calling for the dismantling of apartheid. The note that 186 U.S. companies operating here sent to President Pieter W. Botha a week ago urging his government to lower tensions in black schools was part of an increasingly coordinated campaign by local and foreign businesses to pressure the government for reforms.

A national association of industrialists called the Federated Chamber of Industries has urged the government to begin "true negotiations" with black leaders and offered itself as a "principled mediator." An equivalent traders' organization called the Association of Chambers of Commerce has drafted its own suggested reform constitution that would make South Africa into a multiracial federation.

Ninety-two of the country's biggest corporations recently placed full-page advertisements in local newspapers pledging themselves to work for the abolition of legal race discrimination and for negotiations for power sharing with acknowledged black leaders. Soon afterward, 52 American corporations with interests here, calling themselves the U.S. Corporate Council on South Africa, did the same.

U.S. banks reportedly have warned the Pretoria government that it must move more rapidly toward political reform before they will agree to reschedule the country's $14 billion short-term debt.

Business leaders also have played a leading role in forming a new organization called the National Convention Movement to promote the idea of an all-races convention to work out a new national constitution. A small group, led by the country's most powerful businessman, Gavin Relly, head of the giant Anglo-American Corp., has traveled to Zambia to sound out the exiled leaders of the underground African National Congress.

Cumulatively, it amounts to unparalleled political pressure on the government, and the question now is what effect it will have.

Concerned observers in the United States and other western countries -- viewing the growing pressure in the context of their own societies, where business can exert political influence -- are encouraged, seeing it as the beginning of a process of self-generated reform.

But local observers are less sure, noting that the relationship between business and government is different here than in most western countries. Its potential political leverage is much less, they say, and its prodding may be ignored. Some even think the pressure may be counterproductive, making the government more stubborn.

This view was expressed by a progovernment newspaper, The Citizen, Thursday. Warning U.S. companies in particular that their pressure was bordering on "an unacceptable intrusion into the country's decision making," the Johannesburg daily warned local businessmen, too, that they might provoke a backlash.

"Instead of having the ear of government, they risk an ear bashing from a government that cannot be browbeaten by businessmen into adopting any change of direction that does not conform to its own wishes," the editorial said.

What limits the businessmen's influence, as nearly all of them recognize, is the historical ethnic cleavage between the mostly Dutch-descended Afrikaners, who number 60 percent of the 4.6 million whites, and the remaining whites, mostly of British descent.

As a generalization, it may be said that the Afrikaners control the government, while the ethnic English control the business sector -- and that there has been a tacit coalition between the two in ensuring that the whites control the blacks, who outnumber them, 4 to 1.

This is less true today than it was when Botha's National Party, the mobilizing force of Afrikaner nationalist sentiment, came to power in 1948. Thirty-seven years of political control by people who were once the economic underdogs and an industrial revolution that has made South Africa the most developed country on this continent have wrought major sociological changes.

Thousands of Afrikaners have moved from the farms to the cities, and many are making their way in business. Two of the country's six biggest mining and industrial conglomerates now are controlled by Afrikaners.

A new class of young, urban, upwardly mobile Afrikaners is having a revisionist influence that is working its way slowly through the ossified organs of the National Party.

Hermann Giliomee, an Afrikaner political scientist, calls them the "Boer yuppies," using the word for "farmer" by which the Afrikaners once described themselves in their derivative of the Dutch language. He says their emergence and growing influence is a key factor in causing the split between Botha's National Party and the breakaway Conservative Party of right-winger Andries Treurnicht.

"Botha has followed the Afrikaners to the cities, and under him the government has become much more middle-class," Giliomee said in an interview.

However, Giliomee says that despite the changes there is still a psychological gap. To the Afrikaner nationalists who control the government, business is still seen as essentially the preserve of the English establishment and thus part of the traditional political opposition.

Botha has gone out of his way to woo the business community and involve them in government in a way that his far-rightist opponents regard as heretical. But when it comes to pressure and influence, the English businessmen are still outsiders with limited leverage.

Afrikaner businessmen have more political clout, but they are more reticent about using it, especially when the government has its back to the wall, as it does now. They are aware that there is an element of ethnic disloyalty in joining in the public criticism.

The difference was expressed crisply by Anthony Bloom, one of the most active of the English business leaders in the group that met with the ANC. "Anything I say bounces off Botha like a Ping-Pong ball, and I don't even know whether he will read it, but if Fred du Plessis says it, it's apostasy," said Bloom, referring to the chief executive of a big Afrikaner conglomerate.

The relative silence of the Afrikaner businessmen does not mean that they are not also deeply worried about the state of the country and the economy, said Sampie Terreblanche, a government adviser and an economics professor at Stellenbosch University, the Harvard of Afrikaner academia.

"They are just as worried, but they feel if they go public the government will close up even more," Terreblanche said. "They don't want to antagonize it and make it even more stubborn."

Michael Spicer, a political analyst and public affairs adviser to Relly, thinks the gap is more than just ethnic. He also sees a cultural difference between government and business that is equally wide and includes the Afrikaner businessmen.

The National Party is not only tribal, Spicer says, it is also populist, with its roots among farmers and small-town lawyers who felt exploited by big business.

"Even now that a great sociological change is taking place with many Afrikaners moving into the city, there is still no interchange between government and business the way there is in the United States," Spicer said. "Business does not finance political parties, and government does not draw on people from the business sector."

Curiously, Spicer pointed out, not even the new Afrikaner business class gets drawn into government. "The power the new city Afrikaners have sought has not been political power," he said, "so the cleavage remains even within the tribe."

This gap limits business' leverage on government, Spicer said, "but the leverage is not zero. Business can get things done, but it takes concentrated activity over a long time."