At a time when South Africa is trying to present an image to the world of a society undergoing reform, a detailed study has been published here showing that the core features of apartheid, the country's system of racial separation, are being more rigorously applied than ever.

The study is of an extensive population removal program designed to achieve ethnic compartmentalization. It estimates that more than 3 million blacks have been forcibly relocated over 20 years, and another 1 million are scheduled for removal in the near future.

The effect of most of the removals has been to shift blacks from the 87 percent of the country officially regarded as white into 10 small homelands, earmarked for eventual independence, that together constitute 13 percent of South Africa's land area.

The study examines this resettlement program in the context of a related system for regulating the movement of blacks into the cities, all of which are in the white area, by means of pass laws and influx-control regulations.

It concludes that the result has been to turn the homelands into poverty-stricken labor reservoirs where black workers are locked until white employers in the cities requisition them under a migrant-labor system.

The government portrays the homelands as the means of black liberation, through which the 21-million black population will be able to enjoy political self-determination after independence. Four of the 10 homelands have already been declared independent, but this status has not been recognized internationally.

The study, published as a booklet entitled "South Africa--A Land Divided," was undertaken by Black Sash, a white women's organization that began as a protest movement in the 1950s and later set up counseling offices in the cities to help blacks who became entangled in apartheid's legal complexities.

Through the offices the organization acquired extensive practical experience of the workings of these laws and is widely regarded as the most authoritative source of information on the subject.

The study was prepared by specialists who have worked in the counseling offices and visited the resettlement camps.

The system as outlined by the study operates as follows:

Every black must apply for a pass when he or she turns 16.

The black's fingerprints are taken and stored in a central computer in Pretoria together with name, identity number, place and date of birth and supposed place of residence.

Possession of a pass is not in itself sufficient. It must be stamped with a permit to be where the person is.

Some blacks who have been in the cities for many years qualify for the right to stay. The rest have to apply to a labor officer for a permit, and this is the instrument that serves to exclude homeland people from access to the open labor market.

The pass must be produced on demand to any policeman. A black who does not have one, or whose pass lacks a work permit, will be arrested immediately. More than 2,000 are prosecuted daily under the laws.

Recently the law was changed, shifting the responsibility for illegal employment from the worker to the employer and increasing the fine from $50 to $500. The result has been to make it almost impossible for a black to find a clandestine job in the cities. Previously thousands were prepared to pay the price of periodic imprisonment for the sake of a job and the taste of city life.

The system is being tightened in other ways. As a homeland is granted independence all members of the tribe officially assigned to it are stripped of their South African citizenship and become citizens of the homeland.

They thereby lose all future claim to political rights in white South Africa.

Any member of the tribe born after the homeland's independence cannot qualify for city rights either. Eventually there will be no black South Africans and none with city rights. All will be foreigners able to work in white South Africa only on one-year contracts under the migrant labor system.

All "superfluous" blacks--those not needed by the white economy--are being moved out of white South Africa into the already overcrowded homelands.

This includes the old, the chronically sick and the disabled, as well as women and children who do not qualify to stay in their own right.

Old farmworkers are often removed from white farms where they may have lived all their lives when they can no longer do a productive day's work.

In addition to the huge numbers being moved out of the white area, many are being moved from one black area to another because government policy is to separate the black population on ethnic lines.

The people are loaded into trucks and transported to the new area. Only the handful who own 42 acres of land or more are entitled to compensatory land in the new place.

The rest are placed in "closer settlement" camps on tiny plots where they cannot keep livestock, which means those who have cattle or goats have to sell them at giveaway prices and can no longer live by subsistence farming.

There is seldom any work near the resettlement camps. Fewer than 15 percent of new black work seekers can find jobs in the homelands.

Ethel Walt, one of the contributors to the Black Sash study, writes of the resettlement areas: "The details may vary from one area to another but the one common factor in all is the poverty--the grinding, unremitting poverty and desolation. And the hunger. From north to south across the country the statistics on starvation and infant mortality make chilling reading.

"There is also a sharp increase in poverty-related illnesses such as tuberculosis, as well as periodic outbreaks of cholera and typhoid in areas where the water supply is polluted."