Treatment Action Campaign supporters in Cape Town in June 2008, protesting the South African government's "anti-treatment" policies. (Photo Courtesy Lee Middleton/IRIN)

Activists at the world AIDS forum in Vienna Wednesday lobbied for a 'Robin Hood' tax on financial transactions to defeat the funding crisis gripping the war on AIDS.

It is believed that a 'Robin Hood' tax of just 0.005 percent on all financial transactions would raise some 33 billion dollars per year worldwide.

As a result of economic recession funding by rich nations for poor countries fighting HIV/AIDS fell back slightly last year, to 7.6 billion dollars, after 7.7 billion dollars in 2008.

The decline ended six successive years of double digit increases. In 2002 funding for anti-HIV drugs and other initiatives were a mere 1.2 billion.

The Global Fund to fight AIDS, Tuberculosis and Malaria is seeking 17 billion dollars in pledges from 2011 to 2013.

Campaigners at the AIDS forum said the time was right for to push for innovative financing solutions for development, ahead of a summit on Millenium Development Goals in September and a G20 meeting in November.

"It is up to us to explain to the heads of state that that they do not have any other solution because we know it only depends on political will," said Doute-Blazy, a former French foreign minister.

His own organisation UNITAID has trailed the idea with a small tax on airline tickets, implemented by France and 11 other countries, which has provided drugs to prevent HIV infections from mothers to their babies.