The United Nations and World Bank have called on donor nations meeting in Beijing to raise more than $1bn (£566m) to combat bird flu.
Delegates were told that the spread of the flu was unpredictable
The funds will be largely spent on health and veterinary services in affected countries.
Experts fear bird flu may mutate into a form that can spread easily from human to human, triggering a global pandemic.
One Chinese official told delegates everyone breathed the same air and they should unite to fight a common threat.
"In the fight against avian influenza, no country can stay safe by looking the other way," said Vice-Foreign Minister Qiao Zonghuai.
Many affected countries, he said, had a "significant shortfall of funds" which would seriously hamper their prevention and control efforts.
There have been 79 confirmed human deaths from the H5N1 strain since December 2003, with three more as yet unconfirmed.
Almost all sufferers had been in close contact with infected birds and there has so far been no confirmed case of human-to-human transmission.
A three-year-old boy died in Indonesia on Tuesday, a few days after the death of his 13-year-old sister who had bird flu symptoms.
Both children are suspected of contracting the H5N1 strain and if the suspicions are confirmed, it will bring to 14 the official number of deaths from the virus in Indonesia.
In Turkey, another child became infected with bird flu, bringing the total number of human cases there to 21.
Samples have been sent to the UK to determine whether the Turkish child has the H5N1 strain.
Representatives from more than half the world's nations, plus health and finance officials, are in the Chinese capital for the second international conference specifically convened to deal with bird flu.
WHERE WOULD THE MONEY GO?
East Asia and the Pacific - $635.2m
Eastern Europe and Central Asia - $224.6m
Africa - $147.1m
Middle East and North Africa - $110.1m
South Asia - $76.0m
Latin America and Caribbean - $9.2m
Source: World Bank
Delegates are being asked to pledge $1.2-1.4bn and the European Union has raised its pledge from $100m to $120m with individual member-states expected to pledge a similar amount.
A World Bank official said nearly half the money would be spent in Vietnam, Cambodia, Indonesia, Thailand and Laos, countries where bird populations have been seriously hit by the virus.
Indonesia says it is struggling to pay compensation to farmers hit by a mandatory cull of poultry, and has asked for $500m.
The conference received another boost with the decision by Swiss drug maker Roche Holding AG to produce enough of the anti-viral drug Tamiflu for an extra two million people.
There is already enough of the drug to treat three million people.
The World Bank has forecast that the economic cost to the world's economy during the first year of any pandemic could reach $800 billion.
Margaret Chan, the World Health Organization's (WHO) top pandemic expert, told the conference the cost of acting now was "peanuts" compared to the potential losses in the event of a pandemic.
"Timing is unpredictable and the severity is uncertain," she said.
The bird flu threat is "going more and more towards the western part of the world", Food and Agriculture Organisation Chief Veterinary Officer Joseph Domenech told Reuters news agency in Beijing.
"If the mobilisation of the funds is not coming immediately, in a couple of months we'll need more money," he warned.