A UN agency estimates the AIDS death toll in South Africa in 1999 at a quarter of a million people.
This estimate would mean six-year-old statistics used by President Mr Thabo Mbeki underestimate the impact of the disease.
UNAIDS today said the number of AIDS related deaths in South Africa had increased massively since 1995, a day after a South African paper published a letter from Mr Mbeki stating that HIV/AIDS was not the leading cause of death.
"Routine reporting of causes of death always has a tendency to underestimate AIDS as a cause of death. The reason for this is simply the fact that AIDS 'has many faces' which often leads to a diagnosis other than AIDS, for example tuberculosis, as the cause of death," UNAIDS said.
Some 250,000 people are estimated to have died due to AIDS in South Africa during 1999, according to the most recent statistics published on the Internet by UNAIDS.
The 1995 figure quoted by Mr Mbeki in a list of causes of death is 2,653.
Mr Mbeki said in a letter to Health Minister Mr Manto Tshabalala-Msimang, a copy of which was published yesterday in the Business Daynewspaper, that government spending on health services should be re-examined in the light of World Health Organisation (WHO) statistics he found on the Internet dating from 1995.
The WHO 1995 figures appear to back up Mr Mbeki's assertion that AIDS was not the leading cause of death in the country, accounting for just 2.2 per cent of fatalities - in 12th place, behind external causes such as homicide, accidents and suicides, and other illnesses.
But the WHO list includes TB and pneumonia, diseases which are known to be among opportunistic infections that strike HIV patients as separate causes of death above AIDS.
UNAIDS, which coordinates international action against HIV/AIDS with the WHO, acknowledged AIDS was not the primary cause of death in South Africa in 1995.
But it said the prevalence rate of HIV/AIDS infections in South Africa in 1995 was about 3 per cent. Its published prevalence rate for 1999 is 19.94 per cent of the adult population.
Mr Mbeki has been criticised internationally for having said AIDS might not be directly caused by HIV, despite the fact that South Africa has the world's largest HIV population with 4.7 million infected.