The science of HIV and transmission of the virus will dominate the agenda on the first full day of business at the 13th International Aids Conference in Durban.

Opening the conference on Sunday, South African President Thabo Mbeki said poverty and not Aids was the most dangerous threat to the people of Africa.

Mr Mbeki reiterated his controversial view that HIV is not wholly responsible for Aids, but he did say his government remained committed to fighting the disease.

His stand has been criticised as inaccurate and irresponsible by mainstream scientists.

Thabo Mbeki: "Don't blame everything on Aids"

"The world's biggest killer and the greatest cause of ill health and suffering across the globe, including South Africa, is extreme poverty," Mr Mbeki told the delegates.

"As I listened and heard the whole story about our own country, it seemed to me that we could not blame everything on a single virus."

Hundreds of delegates walked out during his speech.

African epidemic

Mr Mbeki's stance prompted an unprecedented declaration signed by 5,000 scientists that said good scientific work and not "myth" would resolve the crisis.

The six-day conference is intended to focus on how the developed world and its rich drug firms can help curb the Aids epidemic ravaging Africa and other developing countries.

South Africa has one of the fastest growing HIV infection rates in the world. According to the country's Medical Research Council, 1,700 people are being infected daily, adding to the 4.3 million - 10% of the population - who already carry the virus.

Thousands of people demonstrated before the conference

But the South African Government has refused to accept that retro-viral drugs can significantly reduce the risk of transmission from mothers to their babies. It does not provide the drugs, arguing that they are also too expensive.

Mr Mbeki defended his right to appoint members of his own choosing to an advisory panel, referring to his appointment of some scientists who doubt that HIV exists or that it causes Aids.

He said his government would continue to fight HIV and Aids through preventive measures and poverty reduction programmes. This included contributing to the international research into developing an Aids vaccine.

"I believe that we should speak to one another honestly and frankly with sufficient tolerance to respect everybody's point of view with sufficient tolerance to allow all voices to be heard," he said.

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"Some in our common world consider the questions I and the rest of our government have raised about the HIV-Aids issue... as akin to grave criminal and genocidal misconduct."

Earlier on Sunday, Winnie Madikizela-Mandela, the former wife of Nelson Mandela, accused Mr Mbeki's government of failing to address the Aids crisis.

More than two-thirds of the 34.3 million people with HIV or Aids worldwide live in sub-Saharan Africa, according to the UN.