Russia will undo good progress in combating HIV/AIDS and miss the chance to stem the epidemic if it does not offer more help to people who inject themselves with drugs, UN AIDS chief Peter Piot said yesterday.

Piot also warned Russia and Ukraine of a rise in the proportion of women infected with the HIV virus who neither inject drugs nor work as prostitutes - a segment of the population previously considered less vulnerable.

After Sub-Saharan Africa and South Asia the former Soviet Union has the highest number of people who carry the HIV virus which transmutes into the deadly AIDS infection, although the infection rate in the region has slowed over the last few years.

"They are on the right path, the right trajectory but some difficult decisions have to be made," Piot told Reuters in Moscow during a conference on AIDS in the former Soviet Union.

"The region is at a critical point."

Russia and the Central Asian states lie on the main heroin trafficking route from Afghanistan to Europe and drug users injecting themselves with infected needles account for up to 80 per cent of people with the HIV virus.

The former Soviet states have ploughed millions of dollars into combating HIV over the last few years and boosted partnerships between civil society and the government with positive results. Despite a 150 per cent increase in people infected with HIV since 2001 to around 1.6 million, the rate of annual new infections slowed to about 150,000 in 2007 from 210,000 in 2001.

In Sub-Saharan Africa around 22.5 million people are infected with HIV and in South Asia about four million people live with the virus.

"Here the big difference is that injecting drug use is so widespread compared to other countries in the world, millions of people are doing it," Piot said.

Drug usage is high partly because of an economic collapse after the 1991 fall of the Soviet Union which cost millions of people their jobs and livelihoods across the region and the relative cheapness of heroin as it is smuggled to Europe.