Indonesia confirmed its fourth human death from bird flu on Friday amid growing global alarm that the virus would mutate and become a pandemic.

Speaking in New York on Thursday, World Health Organisation chief Lee Jong-wook said the virus was moving toward becoming transmissible by humans and that the international community had no time to waste to prevent a pandemic.

The H5N1 strain has killed 64 people in four Asian countries since late 2003 and also spread to Russia and Europe.

A senior Indonesian health official said tests had shown bird flu killed a woman who died last week in a Jakarta hospital after she was admitted suffering from pneumonia and flu-like respiratory problems.

"It´s positive for H5N1," I Nyoman Kandun, director-general of disease control at the Health Ministry, told Reuters.

Indonesia´s health minister is expected to hold a news conference later on Friday to discuss the results, which had been confirmed by a laboratory in Hong Kong.

The woman, 37, died last Saturday. She lived in south Jakarta near a chicken farm, although health officials have not said how she may have caught the virus.

"Our task now as the government is to make sure the public do not panic. Just like when we get a bomb threat, we need to avoid panic. Up until now, there is no proof that there is human-to-human transfer," Kandun said.

But in a stark warning, WHO chief Lee, a South Korean doctor, said it was only a matter of time before the virus mutated.

"Human influenza is coming, we know that, and no government, no leaders can afford to be caught off-guard," Lee told a news conference. "We must pounce on human pandemic outbreaks with all medicines at our disposal and at the earliest possible moment."

Most of the people killed in Asia since 2003 caught the virus from infected birds. Health experts say the greatest worry is that the highly pathogenic strain of the disease known as H5N1 could mutate and become transmissible between people.

Lee said H5N1 "will acquire this capability -- it´s just an issue of timing." Countries far from heavily hit Southeast Asian states would not be safe because the disease was spreading through migratory wildfowl, Lee added.

Besides Indonesia, bird flu has killed 44 people in Vietnam, 12 people in Thailand and four in Cambodia.

U.S. President George W. Bush unveiled a plan at the United Nations on Wednesday under which countries and international agencies would pool resources and expertise to fight bird flu.

U.N. health authorities have said more cases could be expected in Indonesia, the world´s fourth most populous nation.

The government has launched a vaccination drive for poultry but carried out only limited culling because it does not have enough money to compensate farmers and more than half of all chickens in Indonesia are kept in backyards.

The WHO says the preferable approach is mass culling.

The virus has spread to 22 provinces out of 33 in the sprawling Indonesian archipelago, killing more than 9.5 million poultry since late 2003.

In July, Indonesia confirmed its first human casualties of H5N1 -- a father and his two young daughters in Tangerang on the outskirts of Jakarta. But authorities could not pinpoint the source that infected the family.