The high bird flu alert in Jakarta, where four people have died and 10 people are under hospital observation, does not mean the avian flu outbreak has worsened, the World Health Organisation (WHO) said on Thursday.
The WHO said increased surveillance by the Indonesian government could explain the rise in cases being uncovered, adding there was still no evidence that the risk of human-to-human transmission of the disease was any greater.
"With increased surveillance it's not unusual that you would pick up more cases," said Dr Margaret Chan, the WHO's global special representative on avian flu, reports Reuters.
"If things worsen it could become an epidemic," Indonesian Health Minister Siti Fadila Supari told The Associated Press.
The H5N1 strain of bird flu has swept through poultry populations in large swaths of Asia since 2003, killing at least 63 people and resulting in the deaths of tens of millions of birds.
Most human cases have been linked to contact with sick birds. But the World Health Organization has warned the virus could mutate into a form that spreads easily among humans possibly triggering a global pandemic that could kill millions.
A top WHO official said Wednesday the agency was prepared to begin distributing large-scale quantities of an antiviral drug to treat bird flu in humans "if and when a pandemic starts," informs ABC.