Why Mr. Mbokazi doesn't own his Soweto home

Jenny Menhennick speaks slowly, but with considerable volume to drown out a train that is rumbling past. ''This scheme means you can buy the rights to the land for 99 years, and no one can take that away from you,'' she explains to Eric Mbokazi.

Mr. Mbokazi, a black from nearby Soweto, had seemed to drift from the conversation but perks up at the mention of legal rights. ''That is good,'' he says, nodding approval to his brother seated beside him.

The Mbokazi brothers are part of a steady stream of traffic into the West Rand Administration Board's home-ownership offices here on the dusty, barren outskirts of South Africa's largest black township. Most are looking for ways to become more permanent residents through some type of home ownership in official ''white'' South Africa.

Mrs. Menhennick is explaining the newest option for blacks in urban areas: the 99-year leasehold, which grants blacks rights to government-owned land for that period of time. They can build on the land or improve on existing structures. However, the 99-year leasehold, authorized in 1978, has so far achieved meager results.

In Soweto, with a population of an estimated 1.2 million, just over 1,000 99 -year leaseholds have been registered. For all of South Africa, the number is about 1,600.

Many analysts blame the lack of success of the leasehold system on bureaucratic inertia. After decades of considering the urban black to be a temporary sojourner in ''white South Africa,'' the government was unprepared to pave the way for land rights for blacks. Zoning, surveying, and other steps necessary to allocate legal property rights had not been taken.

Also, many blacks were and still are opposed to the plan. It is seen as just another white-government denial of black rights, falling far short of complete, unqualified freehold property rights.

Here at the government home-ownership office for Soweto, Mrs. Menhennick says between appointments that until very recently most blacks did not understand what the 99-year leasehold system was all about. But, from the increasing number of blacks coming into her office seeking these leaseholds, she surmises that ''it is catching on very quickly now.''

Most applicants here seeking rights to land to build their own home go away disappointed. Even if they can scrape together the estimated minimum of 10,000 rand ($9,400) necessary to build a new house, chances are they will not be granted any land on which to build. There appears to be plenty of land in and around Soweto, but government-approved sites for new homes are in very short supply.

Some analysts of black housing feel the government is deliberately holding back land so urban townships cannot expand. They charge that this strategy drives up the price of existing land and creates a black upper class of homeowners who, with a greater stake in social stability, presumably would be more moderate in political demands than the rest of the black urban population.

Meanwhile, the government itself is falling behind in meeting the need for housing in Soweto. No new housing was built in 1980. At present the government says some 800 units are under construction. This is against the backdrop of a housing shortage of about 55,000 units, according to the Urban Foundation in Johannesburg.

Besides the 99-year leasehold on land, which can be passed on at death to other members of the family, blacks in Soweto can opt for simple homeownership. This means they own the structure on the land and have permission to occupy the land, but have no legal rights to the land.

About 10 percent of Soweto's houses are owned, the rest are rented to tenants by the government. Many blacks have bought houses they previously rented without getting the legal rights under the 99-year leasehold to the land on which their homes are sited.

There is some hope that black home ownership and leasehold land rights will become available to more blacks in the future. The South African government has recently changed its policy to let white developers qualify for the 99-year leasehold rights, although occupancy of the land is still restricted to blacks.

It is hoped that with ''security of tenure'' to the land, white developers will be able to get financing for more large-scale private housing developments in townships like Soweto. As it is today, housing development for the most part is on an individual, one-house-at-a-time basis.

The new policy may also mean that more companies may get involved in major housing developments for their black employees.

Yet Johan Kruger, national housing manager for the privately funded Urban Foundation, says the new policy will not solve the shortage of black housing ''without other incentives'' to builders and developers.

He will not detail what these incentives should be, but says they are part of the so-called Viljoen Committee recommendations presented to the government recently. This report led to the recent policy change permitting whites to have leasehold rights in black areas.

Of course, the housing shortage per se is not the central issue to many blacks. Freehold property rights remain the main goal for them, and allowing large-scale housing development does not address this fundamental question. Indeed, large-scale housing development, particularly by white employers, is seen as potentially becoming a ''golden handcuff'' - perhaps improving living conditions for blacks, but making them more beholden to their employers.