The head of the World Health Organisation, Gro Harlem Brundtland, has told a WHO conference in Winterthur that billions are needed to contain the spread of infectious diseases linked to poverty.
At the centre of the WHO's concerns are HIV/AIDS, tuberculosis and malaria, which account for more than five million deaths annually.
The three day meeting, which ends on Friday, is aimed at fostering a worldwide movement to increase awareness of poverty and disease.
Brundtland hopes to reduce mortality rates in third-world countries by half within the next five years. She estimated it would cost close to $6 billion to achieve this.
She said $2.5 billion is needed for AIDS prevention campaigns, and a further $3 billion to fight malaria and tuberculosis.
The conference brings together 200 experts from 70 different countries. It is a follow up of the G8 meeting, which took place in Okinawa last July.
swissinfo with agencies