"The mythological dragon was slain by Saint George, the original knight in shining armor, but this dragon must be slain by millions and millions of foot soldiers," he said.
Clinton echoed warnings from UN Secretary General Ban Ki-moon and Peter Piot, executive director of the UN agency UNAIDS, at the opening of the six-day conference on Sunday.
There was "no silver bullet" to rid the world of the disease , the ex-US leader said.
"We know there is so much yet to be done: to expand prevention, treatment and care, to strengthen undeveloped health systems," he said.
Clinton remained unfazed as a silent crowd of demonstrators crossed in front of the podium holding banners calling for housing for people with HIV. He used the moment to underline how rising oil, food prices and the mortgage crisis further complicated the lives of people with HIV -- message greeted by loud applause.
More than 22,000 scientists, policymakers and field workers are attending the 17th International AIDS Conference, making it the second largest conference in the history of the disease, and the largest in a developing country.
Funding, access to treatment, beefing up prevention against the human immunodeficiency virus (HIV) and an array of social evils from stigma to violence against women are the headline issues.
On the pharmacological front, delegates do not expect any breakthrough announcement in the arena of new drugs, and there was grim news Monday about the search for a preventative vaccine and an HIV-thwarting vaginal gel.
The UN General Assembly and the Group of Eight (G8) have set the goal of achieving universal access to treatment and therapy by 2010. But despite a big scaleup in the past two years, less than a third of all people in developing countries who need the drugs have been able to access them.
"As the fight against AIDS nears the end of its third decade, we are still facing a huge shortfall in resources," Ban warned the conference.
Clinton however, hailed the approval by the US Congress and signing by President George W. Bush last week of legislation tripling funds to fight AIDS, malaria and tuberculosis to 48 billion dollars over five years in the world's poorest countries, mainly in Africa.
"This is a stunning development for which we should all be grateful," he said.
According to UNAIDS, around 10 billion dollars was spent last year fighting AIDS in poor countries, a massive rise compared with the start of the decade but still more than eight billion dollars short of what was needed.
Just maintaining the current pace of drug scaleup means that funding will have to rise by 50 percent by 2010, but this will still be far short of the target of universal access, UNAIDS said.
Meanwhile, American activists clamored for action, after the US Centers for Disease Control and Prevention (CDC) reported that 56,300 Americans were infected with HIV in 2006 -- 40 percent more than the previous estimate of 40,000 new infections annually.
At least 45 percent of the increase occurred among African-Americans, especially among women and teenagers, while gays and bisexuals accounted for most of the remainder.
The Black AIDS Institute, which includes leading figures in the African-American community, said 1.3 billion dollars were needed to beef up prevention strategies for neglected people in the United States.
"More Black Americans are infected with HIV than the total populations of people living with HIV in seven of the 15 countries" served by President George W. Bush's emergency AIDS plan for Africa and the Caribbean, said the organization's chief executive, Phill Wilson.
The AIDS Healthcare Foundation, the largest US organization on AIDS, called for an immediate allocation of 200 million dollars to test 10 million people for HIV over the next three years.
More than 25 million people have died from AIDS since the disease first emerged in 1981, and 33 million people today are living with HIV, two-thirds of them in sub-Saharan Africa.