Johannesburg — Law and order, it is said, makes good business sense. But there are growing signs in South Africa that the nationwide state of emergency may not. So far the country seems likely to escape the kind of ``punitive'' economic isolation President Pieter Botha acknowledged as a possible danger when he announced the emergency June 12. President Reagan and British Prime Minister Margaret Thatcher, who have repeated their intent to oppose any moves toward sanctions, should make sure of that. Officials here also note that the national currency, the rand, has more than recovered from its brief nose dive when the emergency was imposed June 12.
But by yesterday there were signs that the crackdown risked further unsettling business confidence at home and abroad. [Concerns rise in Zimbabwe. Story, Page 13]. The crackdown may also set back efforts to pull South Africa out of its worst economic recession on record.
At home, a series of sit-ins and strikes by black workers has hit major chain stores. The stoppages are in protest against the alleged detention of union figures without charge or trial. According to one management spokesman, the work stoppages sent executives in search of an audience with the minister of law and order.
From abroad, meanwhile, came what one Johannesburg newspaper termed ``a political bombshell'' -- news of the US House of Representatives' overwhelming approval Wednesday of a bill that would require the complete divestment of US business in South Africa.
Both the strikes and the sanctions vote seemed less worrisome for the South African economy in themselves than in their implications.
A spokesman for one of the retail chains affected by the strikes said there seemed to be ``a lot of sympathy and solidarity'' between striking workers and the union officials who are reportedly under detention. ``We don't know yet how deeply this runs,'' the spokesman said.
Another executive sent a cable to Law and Order Minister Louis Le Grange which said arrests made under the state of emergency had resulted in replacing union negotiators ``with the mob.'' The message suggested that the people detained be charged in court, rather than held by ``administrative'' decision.
The House sanctions package, meanwhile, was expected to be blocked further down the legislative road, either in the Republican-controlled Senate or by veto on President Reagan's desk. But the hefty House majority seemed likely to chill further the climate for US investment in South Africa, and to increase reluctance on the part of Western banks to extend new loans.
Official concern over South Africa's economic woes was underscored earlier this week by remarks the finance minister made to Parliament. Saying that the emergency was necessary and had begun to bring ``stability'' to the marketplace, Barend du Plessis added that a variety of unrest-related problems remained.
These problems include the year-old freeze on loans, increased pressure from abroad for sanctions, and a lack of the business confidence crucial to restoring healthy economic growth in South Africa.
After a small economic upturn in the last quarter of 1985, the economy has slipped back again, according to figures for the first quarter of this year.
``It took South Africa a number of years -- and a leap in the world gold price -- to recover economically after the unrest in 1976,'' a foreign economic analyst. ``This time the unrest has been more serious.''
In Parliament, the one public forum exempt from recently introduced curbs on the news media, opposition politicians have accused the government's emergency rule of undermining confidence rather than restoring it.
The press curbs have come under particularly harsh criticism. Denouncing the government for lowering ``a blanket of censorship over the land,'' liberal opposition leader Colin Eglin charged: ``The information that is coming from the Bureau of Information is limited and relatively unreliable.'' The Bureau of Information is a recent creation of the Pretoria government, and, under the state of emergency, is responsible for conducting daily briefings for the press.
Local and foreign newspapers have taken to running ``censorship'' disclaimers. And, to dramatize the situation, two newspapers, the Star and the Sowetan, have run blank spaces in some editions, where unreportable statements and incidents should have been.