The U.N. health chief said on Tuesday she would make ensuring global access to flu pandemic vaccines a personal priority.

"I am personally engaged in several efforts to ensure access to vaccines in all countries," said Dr. Margaret Chan, WHO's director-general, at the agency's annual assembly in Geneva.

Chan's statement came amid an ongoing battle with Indonesia over H5N1 virus samples. Indonesia has not shared any bird flu samples since last December, arguing that the vaccines that companies could develop from its viruses would be too expensive for its population.

Health minister Siti Fadilah Supari told the assembly that the country had partially resumed sharing samples with a WHO-accredited laboratory in Japan earlier this month, on the understanding that the viruses would not be used for vaccine development without Indonesia's permission.

WHO confirmed that its collaborating laboratory in Tokyo had received three H5N1 samples from Indonesia, but it was unclear whether further samples would be sent.

"Discussions are ongoing among WHO member states to establish the basis for further sharing," said WHO spokesman Gregory Hartl.

Several pre-pandemic vaccines based on H5N1 exist, but as the virus continues to mutate, scientists need to match the latest circulating strain to that in the vaccine, to ensure that the vaccines would work. A draft resolution was introduced by 17 developing countries Tuesday -- and co-sponsored by Indonesia -- calling for a more equitable distribution of vaccines to poor countries.

WHO has suggested the creation of a "virtual" pandemic vaccine stockpile. But such a stockpile would depend largely on wealthy countries donating their own vaccines to poor countries in a global health emergency, and on vaccine companies agreeing to redirect their stocks.

WHO said discussions with donor countries and vaccine companies had begun to try to establish such a virtual stockpile, but offered no details on the progress.

"There needs to be much greater discussions on how large a stockpile should be if you have such a vaccine," said Dr. Keiji Fukuda, the coordinator of WHO's global influenza program. Supari said that Indonesia would need at least 22 million doses of the vaccine, enough to cover at least 10 percent of its population.

The H5N1 strain of bird flu has killed 185 people worldwide since it first appeared on a large scale in 2003, according to the agency.

It is believed that most human deaths have resulted from people having close contact with infected birds, but experts fear the virus could mutate into a form that spreads easily between humans, thus igniting a flu pandemic.