Botha seems to be taking new tack on political prisoners. S. Africa move seen as bid to settle Mandela question

South African President Pieter W. Botha is forging a new formula for the release of political prisoners that is designed to break the impasse over the jailed African National Congress (ANC) leader, Nelson Mandela. In a major speech to Parliament late last week, Mr. Botha announced that the release of Govan Mbeki, jailed for life with Mr. Mandela, was under consideration. Mr. Mbeki is a former chairman of the outlawed ANC, a former member of the ``high command'' of the ANC underground army, and a top member of the outlawed South African Communist Party.

His possible release is not insignificant of itself, but it could also set the stage for the release of other political prisoners and culminate in Mandela's release, diplomats say.

In his address last week Botha moved away from a January 1985 statement in which he said Mandela, jailed for sabotage, would be released if he renounced violence as a means for achieving political ends. At that time, Botha said the choice was Mandela's. Mandela has refused to renounce violence.

By stipulating that the choice was Mandela's, Botha handed the initiative to Mandela, analysts say. But Botha retook the initiative, last week, declaring that renunciation of violence was a critical but not necessarily a decisive consideration. Other factors had to be taken into account, he said. They included the ``intentions of the punisher, the interests of the community and state, [and] the duration of the sentence.''

Mandela's release has been set as a condition by ``moderate'' black leaders for their participation in a ``new deal'' with government. Botha is anxious to persuade black notables to serve on his envisaged new National Council.

The anticipation is that the new policy will start with Mbeki's release. The freeing of Walter Sisulu, former secretary-general of the ANC, and Zephania Mothopeng, president of the outlawed Pan-Africanist Congress, could follow - all prior to freeing Mandela.

The releases will achieve two purposes. It will, it is hoped, inure the the still volatile black townships to the release of black heros, thus preparing them for Mandela's release. And it will enable Botha to gauge the reaction of the ultra-rightist conservative party and its ally, the Afrikaner Resistance Movement, enabling him to retreat if the going gets too hot.

Foreign and local analysts said it is significant that Botha's statement about Mbeki came with his annoucement that he was postponing the next white general election from 1989 to 1992. The move will give him the more time to complete his intricate maneuvers for a settlement with blacks before having to contend with his white ultra-rightist foes at the polls.