South Africa moves to oust blacks but plan draws domestic opposition

South Africa is quietly pushing ahead with plans to transfer 800,000 blacks and large chunks of land to neighboring Swaziland.

Amid strong domestic opposition to the deal, Pretoria is for the moment letting Swaziland act as chief salesman. The government of that tiny nation has been putting its case to other African states. Recently Swaziland's foreign minister was granted air time on South African television to explain why the proposal should go ahead.

More in the background, the South African government is fighting to clear a legal path for the transfer.

This week it will contest a challenge to its action of abolishing the government of KaNgwane - the black ''homeland'' Pretoria wants incorporated into Swaziland. Next month the government will appeal a court decision that rejected Pretoria's proclamation handing over part of the territory of KwaZulu - the other black ''homeland'' affected by the Swaziland proposal.

But the costs of the deal seem to be mounting and the benefits remain mostly undefined.

South African Prime Minister Pieter W. Botha is busy trying to woo his country's Asian and mixed-race population groups into a ''power sharing'' arrangement with the white minority government. The Swaziland deal has not helped his case. Alan Hendrickse, a leading Colored politician with whom the government must deal on the power sharing issue, has criticized the ''lack of consultation'' with blacks in the transfer.

To many critics, the proposal smacks of a return to the ''grand design'' of apartheid (forced racial segregation), which has the aim of removing as many blacks as possible from the white domain of the republic. Tribal homelands have been established for blacks, where they are urged to take ''independence'' and set up their own governments.

These ''independent'' homelands, however, have gained no international recognition. And critics of the policy see in the Swaziland deal a way around this by handing over blacks to a legitimate sovereign state.

The Swaziland transfer comes at a time when the government appears to be trying to finalize its ''homelands'' policy. Pretoria has for years wrestled with the problem of how to ''consolidate'' the homelands into unified geographic units that would be economically able to stand on their own feet.

Complete land consolidation is now seen as impossible and the government has conceded the homelands will never be ''independent'' economically. A government commission has just handed to the Botha cabinet a modified consolidation plan that fits nicely with the Swaziland proposal.

Rather than creating unified land blocks, ''the government has decided in principle on peoples' consolidation,'' the commission chairman said. The government's justification for the Swaziland deal is that it reunites the Swazi people.

However, blacks affected by the transfer seem to oppose it, and at a recent public meeting in Johannesburg there were strong warnings of violence from the South Africans who will automatically become Swaziland citizens if the proposal goes ahead.

Aside from reducing South Africa's black majority by 800,000, most analysts profess confusion at what else South Africa gains from giving away the land.

The commonly suggested quid pro quo for South Africa from Swaziland is a stronger stance against African National Congress saboteurs who often enter the republic through Swaziland. Also, it is speculated Swaziland will lean more favorably toward Pretoria hopes of establishing a ''constellation'' of states in southern Africa with closer economic ties.