The squeeze on jobs; Black S. Africans find fewer jobs, fewer opportunities to seek them

A black man from Soweto becomes a victim of the rising wave of unemployment in South Africa. He will be sent to join the swelling ranks of the unemployed in his rural ''homeland.''

Besides losing his paycheck, he may lose his right to ever return to the city , where employment opportunities are greatest.

Cases like this are growing more frequent in South Africa, according to an organization that advises blacks in such circumstances. They illustrate the pincer effect on black South Africans of rising unemployment and new government initiatives to seal them off from the cities.

Pretoria imposes numerous restrictions on the movement of blacks into and within South Africa's urban areas. This system of influx control has grown less effective as mounting pressures of hunger and poverty push more blacks into the cities, even at the risk of imprisonment and fines.

To make its regulatory barriers less permeable, the Nationalist government has introduced a top-to-bottom tightening of the system, which it intends to push through Parliament in the 1983 session.

The South African government says its barriers to the free movement of blacks have a protective purpose: They shield blacks already in the cities from overcrowding and ''job-poaching'' from outsiders.

The government minister responsible for influx controls, Dr. Piet Koornhof, calls the new regulations a ''genuine attempt to remove hurtful and unnecessary discrimination'' by improving conditions for those already in the cities.

But critics see the entire concept of influx control as an inhumane practice that relegates the millions of blacks outside the cities - who are greater in number than those within the urban areas - to poverty and despair. Further, these critics see the policy as designed mainly to benefit whites by creating a black urban labor pool big enough to sustain the economy but not so big as to overwhelm whites' sense of security.

Whatever its purpose, the controls are biting deeper. Jobs for blacks are drying up as South Africa's economy worsens.

Black unemployment is rising in South Africa. It is now about 8 percent in the cities, and probably twice that in the rural areas, according to estimates by private economists. The measures of unemployment are based on a narrower definition of unemployment than that used in developed nations.

The government appears to be using the rise in unemployment to empty the black urban areas of some ''contract'' workers, who are permitted to come to the cities to work for a fixed time period. Recruitment of contract workers from many rural areas is already being reduced. Contractlaborers who lose their jobs and are sent back to homelands to gain new contracts have slimmer chances of returning to the cities.

The nation's economy apparently can afford a reduction in the flow of new black labor into the urban areas since black urban townships have grown larger than planned through squatting and rising birth rates.

Meanwhile, the Black Sash human-rights organization says conditions of ''landlessness, unemployment, and poverty'' in the so-called homelands are worsening and making the pressure toward urbanization even greater. Calling these pressures ''irresistible,'' the Black Sash has urged the government not to resist the process, but to work to make urbanization take place in ''as orderly fashion as is possible.''

The government's strategy for reducing urbanization appears to be on two tracks. One is long term. Recognizing that the homelands are generally failing to provide for blacks economically, the government is encouraging business and industry to ''decentralize.'' It aims to move jobs away from the central cities, and closer to rural blacks. Businessmen give the plan a mixed chance of success.

The other main track for reducing urbanization appears to be a drastic tightening of influx control. The government's legislative proposal - called the ''orderly movement and settlement of black persons bill'' - would give officials greater power to act unencumbered in dealing with squatters. And the bill sharply increases the penalties on ''unauthorized'' blacks in urban areas.

Under the new law, blacks would lose the 72-hour grace period they now have for being in urban areas. No unauthorized black could be in the city between 10 p.m. and 5 a.m under the new law. This restriction has led the Black Sash to warn of increased police raids, which, under the proposed law, could take place without a search warrant day or night in homes or businesses. Where violations are found, the violator and the occupant of the home would be fined more than $ 400 dollars each.

The stiffest penalty would be levied on employers who hire unauthorized blacks. This fine would be about $4,400, up tenfold from the present level.

Blacks now allowed to reside permanently in the urban areas under so-called Section 10 rights will retain that right under the new law. This right is restricted to blacks who have lived continuously in an urban area since birth, worked continuously in such an area for one employer for 10 years, or have lived lawfully in an urban area for at least 15 years.

But the proposed law makes it more difficult for blacks without permanent urban residential rights to acquire them. Blacks who have lost their South African citizenship because they are classified as residents of a homeland will not be able to gain permanent status. Blacks born in an urban area will have permanent rights in the cities if they can prove that both their parents are permanent urban residents.

Black Sash's president says the effect of the bill will be to reduce legal urbanization ''to the point of extinction.''