The United States has pledged US$410 million ($568 million) towards ending the AIDS epidemic in South Africa, the country hardest-hit.
South Africa has the world's largest population of people living with HIV, at 6.8 million, and the funds will help expand its anti-retroviral program, which provides treatment to more than 3 million patients.
The country experienced 180,000 AIDS-related deaths in 2015, according to the United Nations Program on HIV/AIDS (UNAIDS). Its prevalence rate of HIV among adults, at 19 percent, is one of the highest in the world.
The funds were donated through the US President's Emergency Plan for AIDS Relief (PEPFAR), which also supports projects in South Africa to encourage male circumcision and attempts to reduce new HIV infections in girls and young women.
Delegates are expected to discuss the ambitious target, proposed by UNAIDS, of ending AIDS as a global health crisis by 2030 at the International AIDS Conference to be held in the South African coastal city of Durban next week.
Health Minister Aaron Motsoaledi said while the government expected to take on a larger share of the financial burden of HIV treatment and prevention, it depended on support from the international community.
"We mustn't say that just because we are making progress the job is done," he said. "The job is far from done."
In May, Motsoaledi said South Africa recorded half of the 5000 new infections a week among young women out of 14 southern and Eastern African countries.
Pretoria set up a new state-owned pharmaceutical firm last year to help cut the cost of HIV treatment.
In December 2014, South Africa chose four drug companies, including India's Cipla and local firm Aspen Pharmacare, to make and supply anti-retrovirals to public hospitals.