The growing wave of protests against the South African government has alarmed a broad range of U.S. business groups -- from the U.S. Chamber of Commerce to "mom and pop" sellers of South African gold coins -- and they are mobilizing to block the passage of economic sanctions and other anti-apartheid legislation in the upcoming session of Congress.

As the Free South Africa movement spread across the country this week, officials of some of the country's largest trade associations and companies huddled in Washington to devise a strategy to counter the impact of the protests.

The meeting -- which was attended by officials of the chamber and the National Association of Manufacturers as well as such companies as Mobil Corp., Dresser Industries Inc., and Caterpillar Tractor Co. -- resulted in an agreement that the groups should lobby together against proposals that would ban new U.S. investments in South Africa, prohibit new bank loans, and impose other restrictions on American companies in that nation.

Such measures would only be counterproductive, U.S. companies argue, damaging the $2.3 billion worth of existing U.S. investment in South Africa and increasing the pressure on U.S. firms to pull out without leading to any change in South African internal policies.

"We're the only country that has any leverage in South Africa -- why the hell would you want to shut it off?" said Sal Marzullo, chairman of an industry group for the 128 U.S. firms that operate in South Africa and have signed the Sullivan Principles -- a voluntary code that pledges them to eliminate segregation in the workplace and pay black workers the same wages as whites.

The activities of Marzullo and others is one sign of the mounting apprehension among American companies over the South Africa protests. Rep. Stephen Solarz (D-N.Y.) said this week he planned to reintroduce legislation for a ban on new U.S. investments in South Africa and other measures. That position picked up new momentum Wednesday when 35 conservative Republican House members wrote to the South African ambassador saying they were prepared to support sanctions unless the Pretoria regime moved rapidly to liberalize its policies.

"The vast majority of conservatives share the viewpoint that apartheid is morally reprehensible," said Rep. Robert Walker (R-Pa.), who helped draft the letter.

The problem, as U.S. companies see it, is translating moral opposition to South Africa's internal policies into effective U.S. action that will change them. Supporters argue there are a host of punitive measures that could be taken -- ranging from restrictions on the landing rights of South African Airways to prohibitions on the sale of South African gold Krugerrands -- that would stigmatize white South Africans and pressure them into loosening up on their treatment of the country's black majority.

But critics say many of these proposals would have little effect on the South African economy, although they would hurt various U.S. interest groups. A prime example is the "gold bug" lobby. Earlier this year, the House approved a ban on the importation of South African Krugerrands -- small gold coins that sell for about $350 apiece and have been purchased by millions of Americans as a hedge against inflation.

The Industry Council for Tangible Assets, which represents about 600 precious-metal dealers, mobilized a massive letter-writing campaign among coin owners this year and managed to kill the provision. The council argues that restrictions on Krugerrand sales would undermine the value of existing holdings.

"We do not take a position on the internal situation in South Africa at all," said Donald C. Evans, council president. "We're trying to defend Americans who acted in good faith.

More significantly, critics note, the United States imports hundreds of millions of dollars worth of strategic minerals from South Africa -- such as chrome, platinum, manganese, and uranium -- that are vital to the functioning of U.S. industries, such as steel, autos, chemicals, and fertilizers.