When Percy Qoboza returned to South Africa after spending a year here as a Nieman Fellow, he said last week, he found himself angrier than he had ever been at the injustices of the apartheid system.

That anger must have been apparent in the editorials and news columns of Qoboza's papers, the largest black newspapers in South Africa, because the government has arrested him twice since his 1976 return, and it banned The World and The Weekend World last October.

"In the final analysis, my newspapers were banned not because they committed any treason, but because they told the truth." Qoboza, who was in Boston to give an informal seminar for the Nieman Foundation and to receive an honorary degree at Tufts University, said.

Qoboza was released six weeks ago after spending five months in jail, and has taken over the editorship of The Post.

The Post is owned by the same publishing group, operates out of the same building and has many of the same staff members as The World did before it was banned, Qoboza said he expects The Post's circulation to reach The World's record of 176,000 by the end of the year.

"Prison didn't change me," Qoboza said. "It simply made me more cynical" about the apartheid system and the white-minority government's desire to improve conditions of the black majority.

Qoboza said he was treated relatively well in prison, in part because he was arrested under one of the less severe sections of South Africa's Internal Security Act, and in part because of the international outcry his arrest provoked.

Last to Know

Qoboza said he was never informed exactly what treason the government believed he had committed.

Because he plans to return to South Africa, where his wife and children are now. Qoboza declined to respond to several questions, since the answers might be construed as treasonable by the South African police.

He could not, for example, give an unguarded answer to questions about corporate withdrawal from his country, he said, because the government could consider any call for divestiture as "economic sabotage."

However, he outlined two views on the subject. On one hand, he said, those who believe that the only solution to South African's problems will be a violent overthrow of the current regime call for corporate withdrawal, hoping that the resulting economic chaos will hasten the government's collapse.

On the other hand, Qoboza said, many people believe corporations "can play a vital role in transforming that society." However, he added that outside of "a twinge of conscience here and there," foreign companies operating in South Africa have done nothing to improve the situation of the nation's blacks.

Because "businessmen are not social workers," Qoboza urged the United States government to require American companies in South Africa to recognize their social responsibilities.

Without immediate U.S. government action--and without similar government action from the governments of other countries with investments in South Africa--Qoboza said it seemed unlikely that the business community would take its social responsibilities seriously.

He added, "I do not believe one single person wants to see blood shed in South Africa."

Asked what he will do on his return next month to The Post, Qoboza--who has received several threats on his life since his release from jail--looked a little weary.

Like the rest of those fighting apartheid, Qoboza said, he will do "what my brothers in the South used to do: keep on keeping on.