Africans with AIDS increasingly need access to newer medications in order to survive, but the latest drugs are still priced far out of reach for people who need them, Doctors Without Borders said Monday.

The global medical charity Doctors without Borders (MSF) warned that at one of the continent's longest-running treatment schemes, based in Khayelitsha township outside Cape Town, more patients were showing resistance to first and even second-line treatments.

Sixteen percent of patients at the Khayelitsha programme stopped responding to first-line treatments within five years, MSF said. One quarter of those patients stopped responding to second-line treatments within two years, it added.

New third-line treatments are not available in South Africa, and cost as much as 17 times the price of older drugs, MSF said in a statement released during a conference of the International AIDS Society on treatment.

"What we are seeing in Khayelitsha is what we will soon see throughout Africa if there is not a focused push for urgent change," said Eric Goemaere, medical co-ordinator for MSF in South Africa.

"We need to provide the most robust first-line treatment possible, to detect treatment failure through monitoring HIV levels in the body before patients show symptoms, and to provide access to affordable second- and third-line treatment combinations," he said.

"None of this is happening now, which means that thousands of patients are back on AIDS death row."

MSF urged drugmakers to put their AIDS drugs into an international "patent pool" that being developed by UNITAID, an international drug purchase facility.

The pool will give makers of generic drugs access to new medications in exchange for a fee paid to the company that developed the treatment.

More than three million people in poor countries are receiving AIDS treatments now, but seven million are still waiting for even first-line drugs, according to MSF.

South Africa has the world's largest AIDS caseload, with more than five million people living with HIV.