Black unions gain clout in S. Africa

South Africa's emerging black labor movement is entering a crucial testing period.

More and more blacks see unions as an important area where they can legally exercise power in this white-dominated society. The present challenge to the unions is to maintain their recent surge in popularity amid a quickly deteriorating economy.

One of these emerging black unions, the National Automobile and Allied Workers' Union (NAAWU) took 10,000 workers out on strike in three motor assembly plants in the Port Elizabeth region of South Africa before agreeing July 20 to go back to work. Analysts considered it one of the best organized strikes of black workers in the past decade.

The confrontation was set by conditions now affecting the entire South African labor scene. Workers, pressed by the highest inflation rate since 1920, want hefty wage increases. Business, facing slow growth and recession, is growing more stingy. (The auto workers want a 75 percent pay increase, management is offering about 8 percent.) No wage agreement has yet been reached.

Under these circumstances black unions like NAAWU are under great pressure to deliver to workers the ''decent standard of living'' they are increasingly demanding. What will the unions' tactics be: confrontation, compromise, or acquiescence?

Immediately in the balance for South Africa is whether there will be more labor strife among blacks. The danger is that it could wash over into broader social unrest.

The more long-term question may be the future of unionism among blacks. Many labor analysts say that if unions continue to grow stronger, they will ultimately take on a more political role for blacks, who have no political voice in the republic at present.

Black union membership has increased about tenfold since its most recent trough in 1976, when an economic downturn contributed to a falling off of union participation. Membership has grown most spectacularly in the past two years, aided by both a robust economy and government legalization of black unions. About 300,000 blacks now belong to unions.

Most labor analysts say black unions, many of which are technically multiracial although they are dominated by blacks, have gained enough of a foothold that they will not wilt as they did in the 1970s. The central reasons are that they have gained legitimacy in the eyes of both industry and government , they are better organized, and they are better meeting the needs of workers.

On membership prospects this year, black labor leader Chris Dlamini says that while workers are still joining in great numbers, the unions ''won't be as successful as we were last year because of the recession.''

Dlamini is national president of the Federation of South African Trade Unions - the largest grouping of newly formed black unions. He reasons that rising unemployment among blacks will slow recruitment.

However, union leaders seem less concerned now with total membership numbers than with bargaining effectiveness. Dlamini concedes the majority of strikes by members of the federation have failed because they were spontaneous and not well organized.

The federation is concentrating on stronger organization at the individual plant level. It is also bent on achieving true industry-wide representation and bargaining in three critical industries - steel, automobiles, and textiles.

NAAWU, a federation member, has taken meaningful steps in that direction by closing three automobile plants - Ford, General Motors, and Volkswagen - simultaneously.

Dissatisfaction among black workers led to 342 strikes in 1981, the second biggest strike year on record in South Africa.

The level of strikes in the first half of this year is running at about the same level as early 1981.

Most observers say black unionists will inevitably use their growing economic power for political purposes. But such activity has strict legal limits, and union officials usually refuse to discuss it.

Many of the new black unions have deliberately eschewed linking up with populist political causes. It is partly a strategic decision. In the past leaders of black workers movements often were political figureheads. And when such individuals were banned by the state, the labor movements were left floundering. But unionists also seem to feel that at least for the moment black workers are best served by unions that confine themselves to labor issues.

The government nonetheless appears increasingly suspicious of political links in the black unions. Last year the banning of black union leaders reached a peak , the South African Institute of Race Relations says.

Black unionists, too, have shown a broadening view of what they consider to be labor-related issues. Unions stopped work briefly earlier this year to protest the death of fellow unionist Neil Aggett while in police custody.

There was much labor unrest last year when the government announced plans to introduce pension legislation black workers did not like. The unions succeeded in forcing the government to drop the concept. An analyst characterized the incident as a major political victory for black labor unions.

''Black unions are just starting to taste power. This is just the beginning of much more significant demands,'' a university labor specialist with close ties to black unions predicts.