Deputy President Kgalema Motlanthe has urged aid donors not to "disinvest in health", especially not HIV and Aids.

Motlanthe who addressed 25000 delegates at the 18th International Aids Conference in Vienna, Austria, yesterday said: "We need renewed commitment for consistent, sustained and predictable financing mechanisms. I would argue that now is not the time to disinvest in health."

The conference, which is held every two years, brings together policymakers, people with HIV and people working in the field to discuss evidence-based policy and responses to the pandemic.

Motlanthe told the delegates that investment had become vital in "realising the right to health".

"We cannot . allow the recession to take precedence over the right to health and the principles enshrined in the Universal Declaration of Human Rights," he said.

This came after support from US President Barack Obama's emergency plan for Aids relief for antiretroviral treatment in sub-Saharan Africa was reduced, and HIV/Aids funding was frozen.

Along with other donors that have reduced their funding, the World Aids Campaign, the world's biggest Aids funder, is facing financial shortfalls.

Motlanthe also spoke about South Africa's "progress in many key aspects of our collective national response", including, he said, the effectiveness of the prevention-of-mother-to-child-transmission programme, which Motlanthe said had experienced a "dramatic improvement".

"Antiretroviral treatment is provided to well over 80% of diagnosed mothers, and in some of our 'priority districts', we are succeeding in reducing mother-to-child-transmission to below 6%," he said.

Studies conducted in South Africa in 2002, 2005 and 2008 had shown a 35% drop in new Aids infections in the country between 2002 and 2008 - bearing testimony to the need for funding of antiretroviral drugs.

"Therefore, we continue to make the investments necessary, and are working hard to ensure that they are proportionate to the response that is required, even in the face of declining revenues," Motlanthe said.

A Canadian study found that antiretrovirals not only halved the number of new Aids cases but were also a weapon for preventing viral spread.

The study examined the population of British Columbia and the coverage of antiretroviral treatment and new cases of infection between 1996 and last year.

Over this period, the annual tally of new cases fell by 52%, the researchers found.