The fight against HIV/Aids, tuberculosis and malaria will cost some $87bn (R770bn) between 2014-16 if the three scourges are to be kept in check, a report showed.
The Global Fund to fight Aids, tuberculosis and malaria said it estimated $87bn was needed to "provide essential services for effective treatment to vulnerable populations".
The battle against Aids alone will cost some $58bn in 2014-16, it said, with tuberculosis needing $15bn and malaria $14bn.
"Today, we have a historic chance to control completely these diseases. If we do not take it, the long term cost will be colossal," Global Fund head Mark Dybul said.
If all the funding is provided, it will be possible to treat some 17 million tuberculosis patients and to prevent millions of new Aids and malaria cases each year, the group said.