Cutbacks in rich-world funding for AIDS treatment could sentence millions of sufferers to death for lack of access to anti-retroviral (ARV) drugs, Medecins Sans Frontieres warned Thursday.

"Donors have started to shift their support away from HIV/AIDS, and funding is not keeping up with the need," the medical charity, known in English as Doctors Without Borders, warned in a report ahead of a major AIDS conference in Vienna next week.

"If nothing is done, most of (those infected with HIV) will die within the next few years," it said, in a study based on fieldwork in eight African countries.

According to MSF, many donors have frozen their contributions to the fight against AIDS — partly due to the financial crisis — with the United States planning to cut its support for ARV drugs in Mozambique by 15 percent over the next four years.

The Global Fund to Fight AIDS, TB and Malaria is trying to raise $20 billion for the next three years.

So far it has received just a few hundred million dollars, the author of the report, Mit Philips, told journalists.

"It is a very frustrating feeling to see that in spite of the achievements that have been made... the international donors, for the moment, show less interest and less resolve to continue to support the fight against HIV/AIDS," she said.

"It's as if they want to give up the fight halfway through. We want to tell them: 'you cannot turn back now on AIDS treatment, it's too important'."

While some three million HIV patients now have access to anti-retroviral drugs in Africa, the continent worst affected by the virus, another six million were still without treatment, MSF warned.

By reducing funding, donor countries would ensure that even less patients received care, or received it too late, it added in its report.