The hard-pressed South African Health Ministry say they cannot afford the drug AZT, even though the makers of the drug, Glaxo Wellcome, are reported to have offered them a substantial discount.

Western countries have been promoting the use of AZT to pregnant women as a way of reducing HIV transmission.

Zackie Achmad describes what the protestors hope to achieve

UK Aids organisations say research shows the number of babies born to HIV positive mothers who themselves become infected falls by two-thirds if the mother takes AZT and does not breastfeed.

However, the drug is very expensive.

An estimated one in five pregnant women treated in public hospitals is HIV-positive and the cost of private treatment at about $500 is way beyond the reach of most South Africans.

Zackie Achmad, spokesman for the National Association of People Living With Aids, said the planned demonstration outside Glaxo Wellcome was demanding drugs be sold at cost price to assist in treating pregnant women.

"The cost of treating babies with HIV or AIDS is much higher than preventing transmission from mother to child," he said.

Not cost-effective

The Health Ministry says the cost of providing treatment would be nearly £1m and with the benefits of AZT still far from clear it was not cost-effective.

Vincent Hlongwane explains why the government will not meet the cost of AZT

Health Ministry spokesman Vincent Hlongwane said the government was concentrating its budget on information and awareness campaigns.

"We can't throw all our money - the limited resources - on just one intervention which is not 100% foolproof," he said.

Rape concern

Women's groups also say the drugs can reduce the chances of contracting HIV if administered within 24 hours of sexual intercourse.

Journalist and rape victim Charlene Smith: Government should supply drugs to rape victims

Concern is being expressed at the increased danger women face of infection from rape.

People Opposing Women Abuse, Powa, says police statistics grossly under-estimate the true extent of rape in South Africa.

They say that for every reported rape, 35 victims stay silent - resulting in a rape occurring every half-minute in South Africa.

South Africa is among the most crime-plagued countries in the world with 116 rapes per 100,000 - nearly double the annual murder rate of 59 per 100,000 in 1998.