A new report says only a third of people worldwide who need life-saving HIV drugs are actually getting treated.

Image caption Life-saving HIV medicine

World leaders had pledged to achieve universal access to HIV medication by the end of this year - but that target won't be met.

The joint report is by the World Health Organisation (WHO), the UN's AIDS programme and UNICEF.

It warns that poorer countries must "substantially ramp up" what they spend on HIV/AIDS.

Most countries need to look seriously into increasing their domestic spending on HIV/AIDS Dr Gottfried Hirnschall, World Health Organisation

The report says there have been "hard-won gains" - but it also makes clear how much work remains to be done.

It's estimated 5.25m people in developing counties are receiving vital antiretroviral drugs, to slow down the virus that causes AIDS.

That number has grown by 1.2m in the past year - but experts believe 14.6m people in total need treatment.

The overall figure has grown, because of new WHO guidelines saying that treatment should start at an earlier stage.

The director of the WHO's HIV/AIDS department, Dr Gottfried Hirnschall, said: "Some countries - such as Rwanda - have shown that universal access to treatment can be achieved.

Millions of people are alive today as a result of investments in HIV over the past few years. WHO/UNAIDS/UNICEF report

"Zimbabwe has increased access by 50% in the past year - despite being heavily compromised, politically and economically.

"And South Africa has had an incredible catch-up phase, despite being a late starter.

"But given those success stories, we need to sustain the momentum - and be smarter in making the case."

'Chip in own resources'

UNAIDS recommends that countries most affected by the virus should allocate between 0.5% and 3% of their government revenue to tackling the problem.

Dr Hirnschall said: "Most of the countries that need to do this aren't yet reaching the 0.5% mark.

"They have to chip in their own resources and look seriously into increasing their domestic spending, to better complement external funding."

The report found that just over half of pregnant women who tested positive for HIV were assessed for drug treatment - up from 34% the previous year.

The authors said: "Millions of people are alive today as a result of investments in HIV over the past few years.

"Yet this evidence becomes available at a time when the global economic crisis has put the sustainability of many HIV programmes at risk.

"After years of considerable increases in international assistance, funding remained essentially flat over the current period."

Next week, it will become clear how much money wealthier countries are donating in future to the Global Fund to fight AIDS, tuberculosis and malaria.

Dr Hirnschall said: "There have been promising signals from some countries, who've already made pledges.

"It's clear things won't be easy though. We have to be strategic in explaining what's needed, and how investment can help other health and development outcomes."