An African National Cogress leader in parliament has challenged ANC MPs to take the lead in breaking the stigma attached to people who are infected with HIV, the virus that causes Aids.

Describing Aids as a "biological disaster", the chair of the ANC caucus, Thabang Makwetla, said shame associated with being declared HIV-positive was one of the factors that contributed to the silence around the disease.

Makwetla said the ANC had to be "exemplary" in the fight to change attitudes over the disease.

"As the ANC we need to lead in this regard to change attitudes associated with being infected with the Aids virus," he said.

Makwetla's statement follows reports that in February the minister of health, Manto Tshabalala-Msimang, warned ANC MPs at a caucus meeting to use condoms during sex.

The timing of Tshabalala-Msimang's warning caused speculation in the media as it followed the death of Mpumalanga ANC MP Mthunzi Vilakazi, reportedly from an Aids-related condition following a short illness.

The party would not comment on the cause of Vilakazi's death.

Last week ANC parliamentary spokesperson Pieter Venter said: "It is a personal matter and we will not comment on people's personal health."

Makwetla would also not be drawn on the reports.

Contacted at her Witbank, Mpumalanga home this week, Vilakazi's wife, Gloria, said her husband had died from complications arising from kidney and liver failure.

Tshabalala-Msimang said that at least one in 10 people or 10 percent of South Africa's 40 million population were already infected with HIV.

The ANC has 266 members in parliament. If MPs have Aids in the same proportion as the general population, then 26 are HIV-positive.

It is in this context that the health minister and other senior ANC leaders have been issuing safe-sex warnings to party members.

"The ANC has a calibre of leadership which should be able to rise above the stereotypes associated with Aids. Until such time that we are able to remove the stigma, we will be unable to make a timeous intervention," Makwetla said. "We should start seeing Aids for what it is, a biological disaster visited upon humanity, and stop blaming individuals."

Makwetla wants ANC MPs and other senior officials in the party to admit their HIV status publicly.

PAC MP Patricia de Lille caused a stir in parliament recently when she challenged politicians to undergo HIV tests and declare the results in public to encourage testing among the rest of the population.

De Lille said this week some politicians were willing to take up her challenge, but others had pointed out that their rights to privacy were protected by the constitution.