More than one million HIV-positive people are receiving anti-retroviral therapy in sub-Saharan Africa, a UN agency says.
HIV drugs have improved, but much more needs to be done
The World Health Organization says there has been ten-fold increase in treatment since December 2003.
The UN's goal is to provide universal access to HIV prevention programmes, treatment, care and support by 2010.
WHO HIV/Aids Director Dr Kevin De Cock told Aids conference delegates in Canada much still needed to be done.
Although sub-Saharan Africa has the greatest number of people on treatment, and the second-highest rate of treatment coverage among those who need it, the region still accounts for 70% of the global unmet treatment need, Dr De Cock said.
"We have reached just one-quarter of the people in need in low and middle-income countries, and the number of those who need treatment will continue to grow," he said.
"Our efforts to overcome the obstacles to treatment access must grow even faster."
Some 24% of people needing ARV treatment worldwide were receiving it by June 2006, he added.
Earlier the UN special envoy on Aids, Stephen Lewis, accused US policy of undermining the efforts of African countries to fight the HIV epidemic.
He said President George Bush's $15bn Emergency Plan for HIV/Aids was too focused on promoting abstinence.