WHO regional director Shigeru Omi said measures to contain birdflu included a large-scale administration of antiviral drugs, quarantines, travel restrictions and social distancing, such as the closure of schools, reported The Jakarta Post.

"We still believe it is possible to stop or delay a pandemic by implementing rapid containment measures very quickly," Omi said.

"But if we fail, the consequences for societies, economies and global health could be immeasurable," he added.

He made the remarks at the Association of Southeast Asian Nations (ASEAN) Secretariat Tuesday, when the regional grouping announced it had begun stockpiling influenza drug Tamiflu in the region in the case of a possible pandemic.

Omi said he believed the stockpiles, which would be stored in Singapore and reserved for an early response to an influenza pandemic in the region, would help ASEAN countries provide a rapid response.

"Many experts say that for containment to be successful, we must take action within a very narrow window of opportunity: about two to three weeks," he said.

Indonesia has the world's highest mortality rate from avian influenza, with 26 deaths from 34 confirmed cases of the virus. It also has the second-highest human fatalities from the virus after Vietnam which has reported 42 deaths.