United States President George W Bush has signed legislation tripling funds to fight the killer diseases of AIDS, malaria and tuberculosis in the world's poorest countries, mainly in Africa.

Congress approved a package earlier this month, which lifted funding for the five-year program from $15 billion, set in 2003, to the $48 billion signed into law by Bush yesterday.

"This bill means $48 billion to fight human misery, with enthusiastic support across party lines," Physicians for Human Rights (PHR) said.

The new programme drops a requirement for one-third of the anti-AIDS funds to be used to promote sexual abstinence and lifts a ban on HIV-positive foreigners entering the United States.

PHR said the travel ban on HIV-positive visitors "has been an embarrassment to this country for many years" and praised the new law for doing away with it.

Democratic Speaker of the House of Representatives, Nancy Pelosi, has praised the bill for taking the global fight against AIDS, tuberculosis and malaria "from the emergency phase to the sustainability phase."