OHANNESBURG, March 30 — Peter Mokaba is a member of Parliament, a senior official in the governing party and a fiery orator who rallied a generation of young blacks to the fight against apartheid.

But he now has a new, controversial calling: explaining why the world should stop worrying about South Africa's AIDS epidemic.

"H.I.V.? It doesn't exist," Mr. Mokaba said this week as he settled into his honey-colored couch. "The kind of stories that they tell that people are dying in droves? It's not true. It's not borne out by any facts.

"Where the science has not proved anything, we cannot allow our people to be guinea pigs," he said, outlining his concerns about the AIDS drugs commonly used in the West. "Antiretrovirals, they're quite dangerous. They're poison actually.

"We cannot allow our people to take something so dangerous that it will actually exterminate them. However well meaning, the hazards of misplaced compassion could lead to genocide."

Mr. Mokaba, 43, has been dismissed as a misguided renegade for promoting AIDS theories that have been roundly rejected by the World Health Organization, the National Institutes of Health near Washington and scientists and officials here and abroad.

Joao Silva/The New York Times Peter Mokaba has incited a controversy by arguing that H.I.V. does not exist and AIDS drugs are poisons.   Topics  Alerts South Africa Acquired Immune Deficiency Syndrome (AIDS) Create Your Own | Manage Alerts Take a Tour Sign Up for Newsletters

Officials in the governing party, the African National Congress, emphasize that Mr. Mokaba was defeated during a debate this month in which the party formally accepted "the assumption that H.I.V. causes AIDS." But critics say Mr. Mokaba's prominence — and the willingness of the leadership to debate his views — leaves little doubt that a small group of politicians still questions the basic assumptions about AIDS, even while the disease devastates the country.

South Africa's AIDS skeptics came to prominence two and a half years ago when President Thabo Mbeki mused publicly about the safety of AIDS drugs and whether H.I.V. causes AIDS. He withdrew from the debate after critics said he was allowing people to assume they could engage in risky sexual behavior by suggesting that poverty, more than H.I.V., was the crucial factor in the spread of the disease.

But the questions that Mr. Mbeki raised still simmer within the ruling party. In its statement released last week, the party referred to the doctors, politicians and advocates who were demanding the widespread distribution of AIDS drugs as supporters of "pseudoscience."

This month, Mr. Mokaba started to promote his views within the party and among its allies in the Communist Party and the trade unions. His campaign has stirred a furor here in South Africa, where more people are infected with H.I.V. than in any other nation. One in nine South Africans, and one in four adults, are believed to be living with H.I.V., government officials say.

Some senior party officials have distanced themselves from Mr. Mokaba, emphasizing that South Africa's AIDS programs have been and continue to be based on the assumption that H.I.V. causes AIDS. Health officials have hastened to point out that the government allocated about $100 million in new spending on conventional AIDS programs this year.

In recent weeks, former President Nelson Mandela and former Archbishop Desmond Tutu have pressed the government to do even more and to expand a pilot program that provides AIDS drugs to pregnant women infected with H.I.V. to reduce their risk of transmitting the virus to their newborns.

But Mr. Mokaba, the former deputy minister of tourism, says growing numbers of people are eager to hear what he has to say. He does not deny that something is attacking the immune systems of many South Africans, but he believes it might be malnutrition or other common illnesses.

He argues that H.I.V. does not exist and cannot be spread through sexual intercourse, that AIDS drugs are deadly and that the epidemic itself is a fiction created by multinational drug companies hoping to boost their profits by forcing poor countries to buy AIDS drugs and by financing researchers to terrorize the public with lies about AIDS.

"There's a small minority of very senior people in the party who support the dissident view," said Saadiq Kariem, the party's national health secretary, who has described Mr. Mokaba's campaign as "irresponsible."

"The implications of this are enormous and disastrous," said Dr. Kariem, who is an epidemiologist. "People have already come to me and said, `If H.I.V. doesn't cause AIDS and AIDS isn't sexually transmitted, why am I wearing a condom?' "

In the history of South Africa, the white government long abused science to oppress the black majority. Apartheid-era scientists developed poisons to kill black people and tried to develop drugs to make them sterile. In that climate, Mr. Mokaba's argument meets with some acceptance. Even his critics say that drug companies have sometimes lowered their standards when testing medicines in third world countries.

Such concerns were heightened here this month when the drug company Boehringer Ingelheim of Germany announced that it was withdrawing its application to market the AIDS drug nevirapine in the United States. The drug, which reduces the risk of H.I.V. transmission from mother to child, is an important topic in South Africa.

A judge has ordered South Africa to distribute nevirapine at public hospitals that have adequate staff and expertise. The government is appealing the ruling, saying the drug should be tested before it is distributed beyond the government's pilot programs.

Nevirapine is still prescribed legally in the United States. But officials at the Food and Drug Administration have raised questions about "procedural" problems with the data from the drug trial in Uganda, which was completed in 1999.

This week, officials from the National Institutes of Health emphasized that they believed nevirapine was safe and effective and that the Food and Drug Administration was concerned only about problems with paperwork and documentation in the trial. The United Nations and the World Health Organization issued a joint statement reiterating that their experts, too, were convinced that nevirapine was safe.

"There's no question that the drug works," said John Ring La Montagne, the deputy director of the National Institute of Allergy and Infectious Diseases, a branch of the National Institutes of Health. "We believe the studies were done to extremely high standards."

But the questions raised by the F.D.A. — and the debilitating side effects that sometimes accompany the use of AIDS drugs — have fueled worries about the safety of nevirapine here.

"I think it's completely explainable," Helen Schneider, director of the Center for Health Policy at the University of the Witwatersrand, said of the persistent questioning about AIDS. "There's a very recent history of direct conspiracy against black people in this country." Besides that, she said, "People can't cope. What you're seeing is this enormous struggle to come to terms with this problem."

Health officials emphasize that they are still running a conventional AIDS program that focuses on preventing the disease, distributing condoms, treating opportunistic infections and providing AIDS drugs to pregnant women in the pilot sites.

"In a practical way, the debate within the A.N.C. really does not affect what we are doing," said Dr. Ayanda Ntsaluba, the director general of South Africa's Department of Health.

"I would have been more concerned if I got the impression that we were being diverted from the current program at government," Dr. Ntsaluba said.

"But a conscious decision has been taken to prioritize these programs, whatever debates are going on."

Smuts Ngonyama, a spokesman for the party, said Mr. Mokaba speaks for himself, not the party, although many members share his concerns about the safety of AIDS drugs. Mr. Ngonyama said he could not stop Mr. Mokaba from promoting his ideas, even though some people believe he is damaging the party's reputation.

"How can you have a situation where you must ban ideas?" Mr. Ngonyama said. "We are coming from a situation in this country where organizations were banned, newspapers were banned, people were banned. Are we returning to that stage now?"

Mr. Mokaba said he supported the government's decision to promote condoms because they prevent sexually transmitted diseases. But he said he would continue to spread his message despite the cries of outrage from his critics.