The effect of Aids has started to hit South African firms' profits, a survey suggests, with mining and manufacturing the worst affected.
One in three miners at Harmony Gold are HIV positive
More than 60% of mines surveyed by the Bureau for Economic Research had lower profits as a result of HIV/Aids.
The survey, carried out on behalf of the South African Business Coalition on HIV and Aids, found profits at about 50% of manufacturers had suffered too.
Retail, wholesale, motoring, building and construction were less affected.
But these sectors expect the impact of Aids to escalate over the next five years.
As well as being the two sectors most affected by Aids, manufacturing and mining also represent the two largest segments of the South African economy, accounting for about 22% and 13% of its gross domestic product.
In both sectors, absenteeism due to ill health is a major problem and is driving up costs, the survey found.
Some miners and manufacturers are being forced to invest in machinery or equipment to reduce their dependence on labour, said the South African Business Coalition on HIV and Aids (Sabcoha).
Some are planning to take on extra staff to offset low labour productivity, absenteeism and the death of workers from Aids.
Sabcoha chief executive Brad Meares cited gold miners AngloGold Ashanti and Harmony Gold as the worst affected.
"Each has estimated that approximately one in three of their employees are currently infected with HIV," he said.
Harmony estimates that HIV/Aids related expenses could cost their company between $2 and $5 per ounce of gold produced.
The Bureau of Economic Reseach survey was carried out between July and August this year and involved more than 1,000 companies in a range of sectors.
"The survey results suggest that a substantial number of South African companies are already suffering the consequences of HIV/Aids," said Mr Meares.
But he pointed out that few companies apart from those in mining or financial services - also included in the survey - mentioned the impact of Aids on their businesses in their annual reports.
More than five million of South Africa's population of 45 million are infected with the killer disease, making it one of the most hard-hit countries in the world.
The South African government has been criticised for not doing enough.
Sabcoha said large companies are leading the fight against Aids, but that smaller companies had made less progress.