Some 200 experts huddled in Geneva on Thursday to debate experimental treatments for the Ebola virus as the world's worst-ever outbreak raged in west Africa, having killed more than 1,900 people so far.

The experts are meeting behind closed doors in a meeting organised by the World Health Organization and include policy makers, ethicists, clinicians, researchers and patient representatives from the affected countries.

"The current west African Ebola outbreak is unprecedented in size, complexity and the strain it has imposed on health systems," WHO said in a statement.

"There is intense public interest in, and demand for, anything that offers hope of definitive treatment."

The meeting aims to review and evaluate the current developments of therapies and vaccines for the virus, inform authorities of affected countries about treatments available, and ease contacts between countries affected by the disease and countries producing treatments.

Global health experts have stepped up their warnings in recent days that world leaders need to do more to address the epidemic, which is most prominent in Guinea, Sierra Leone and Liberia.

The outbreak of Ebola, transmitted through contact with infected bodily fluids, has sparked alarm throughout the region but also further afield, with scientists scrambling to come up with treatment.

In early August, an expert panel convened by WHO said that unproven treatments could be offered under certain conditions.