The Global Aids Alliance has welcomed the news that a generic and cheaper Aids treatment has been cleared by the US Food and Drug Administration (FDA).
The US government only buys Aids drugs approved by the FDA.
The treatment is made by South Africa's largest drug maker Aspen Pharmacare.
FDA clearance means the product can now be purchased by relief agencies funded by President George W. Bush's $15bn (£7.9bn) Aids relief programme.
It is the first time the FDA has approved a generic Aids drug made by a foreign company.
The Bush administration has been criticised by Aids campaigners because of its policy of only buying drugs that have been cleared by the FDA.
In practice, this has meant that recipients of US Aids money have not been able to use it to buy cheaper generic drugs. Now relief agencies funded by American programmes will be able to buy the Aspen treatment.
Aspen's package includes one pill that is the generic equivalent of Combivir made by UK's GlaxoSmithKline. The second tablet is nevirapine, the generic version of Virupan which is made by Germany's Boehringer Ingelheim.
The two firms have granted licenses to Aspen to produce the drugs.
More to do
The Global Aids Alliance, a Washington DC based pressure group, consider the movement a positive development but warned that "the product that was approved is not a fixed-dose combination and, as a result, is not as easy to take".
Millions of people are still waiting for Aids medication
It also said the company would not have had the drug approved "without a positive relationship with several brand name companies, something not all producers of essential, generic medications enjoy".
The Global Aids Alliance also highlighted a report from the World Health Organisation (WHO) which said that, despite some progress being made, there remains a $2bn shortfall to finance the objective of giving medication to three million of the 5.8 million people with Aids living in developing countries who need the medication.
WHO said the number of people on HIV/Aids drugs treatment in the developing world almost doubled during 2004, but this still represented only 12.4% of those who needs them in order to survive.
"The 3 by 5 goal is a solemn promise made to the most desperate people in the world, and we cannot allow a gap of $2bn to stop this encouraging progress," stated Dr Paul Zeitz, executive director of the Global Aids Alliance.