A 5-year-old Indonesian girl from Central Java province has died of bird flu, a Health Ministry official said on Wednesday.

The girl from Wonogiri, who had fallen ill on May 8, died last Thursday after being treated in hospital in the town of Solo for fever and respiratory problems, said Suharda Ningrum of the ministry's bird flu centre.

Authorities were still investigating the case, but at least 20 chickens had died suddenly near her home, the official said.

Contact with sick fowl is the most common cause of human infection.

The girl's death brings the number of confirmed human fatalities in Indonesia to 77, the highest in the world.

Millions of backyard fowl live in close proximity to humans, and keeping backyard chickens is ingrained in Indonesian culture.

Authorities in some areas have made efforts to alter behaviour, but health education campaigns have often been patchy and rules difficult to enforce. Scientists fear the virus could mutate into a strain that spreads easily among people, triggering a pandemic that would sweep the globe.