UN hails Asian transparency over bird flu
He highlighted Indonesia, the country worst hit so far by bird flu, for its transparency in alerting global health authorities to any new cases.
"The government of Indonesia tells the world when it has problems," Nabarro said.
Indonesia's health ministry reported earlier on Wednesday that a five-year-old girl has died of bird flu, raising the nation's toll to 89.
Bird flu is usually transmitted directly from infected birds -- typically poultry -- to humans.
However, scientists fear that the virus could eventually mutate into a form easily transmissible between people, triggering a global pandemic that could potentially kill millions.
Nabarro said that H5N1 is "entrenched" in the poultry populations of at least six countries -- Indonesia, parts of northern Egypt, Nigeria, Bangladesh, China and Vietnam.