The world is more than half way to providing drug treatment for HIV to all those who need it, Aids experts said yesterday – but there may not be enough money to finish the job. In 2011, more than eight million people in developing countries were receiving antiretroviral therapy, a 20 per cent increase on the number in 2010.

The rate of growth is on track to achieve the target set in 2011 by the UN of 15 million HIV infected individuals receiving treatment by 2015, according to Michel Sidibé, executive director of UNAIDS, whose latest report is published today ahead of the 19th International Aids Conference in Washington next week.

Mr Sidibé said the world "deserves no less than a future of zero new HIV infections, zero discrimination and zero AIDS-related deaths". "The world is investing in this vision and the investment is paying off," he said.

But the international charity Médecins Sans Frontières (MSF) said progress was still too slow. Eric Goemaere, a senior MSF doctor, said: "Almost one in two people don't have access to the medicines they need to stay alive.

"If we are going to reach all the people who need treatment we are going to have to double the pace. Every day more people need to be put on treatment than the day before."

The UNAIDS report shows that while domestic funding for HIV has increased by 50 per cent since 2006, international donations have remained flat since 2008. Total resources have not increased, it said.

An extra 1.4 million people began receiving HIV treatment in 2011, but 2.5 million were newly infected, including 330,000 children. The total population living with HIV rose to 34.2 million, the highest level, reflecting the success of treatment in keeping people alive.

Two major threats lie ahead – the continuing shortage of funds caused by the global economic collapse – and the growth of drug resistance. The latter is currently low in most countries but rising in some – and the costs of combination treatments to combat it can be punitive – up to $6,000 a month.

In numbers: HIV and Aids

8m The number of people with HIV receiving antiretroviral treatment last year, up 20% since 2010 and half way to the UN's 15 million target by 2015.

2.5m The number of new HIV infections in 2011, down 20% in a decade.

24% The fall in child HIV infections in the two years from 2009 to 2011.

1.7m The number of people who died from Aids in 2011, down 24% from its peak in 2005.

2 Infection rates in women aged 15-24 are twice as high as men in the same bracket.

34.2m The number of people living with HIV in 2011 – the highest number since records began.