JAKARTA (AFP) -- Significantly reducing the risk of deadly bird flu in Southeast Asia, the region hardest hit by the virus, could take up to a decade, the UN official heading the global fight against avian influenza said.

In an interview with AFP, David Nabarro said changing traditional farming practices across the vast region to reduce the risk of a human pandemic emerging would take several years and a huge political commitment.

However he said the virus, which has killed 142 people in Southeast Asia and 165 worldwide since resurfacing in 2003, does not appear to be mutating into a form easily transmissible between humans.

"During the time that I've been in this job, I have seen no increase in the risk of a pandemic," he said.

"The virus does not seem to have evolved in ways that suggest that it's moving towards being more transmissible between humans, the risk is staying about the same," he said in Indonesia, the nation hardest-hit by avian flu.

Scientists fear that the deadly H5N1 strain could mutate into a form easily transmissible between humans, sparking a pandemic which could kill millions.

H5N1 has resurfaced in humans in Indonesia after an apparent lull with five deaths this year, and in poultry outside the region, including, for the first time, in Britain.

Awareness of the threat has increased hugely as well as the need for effective responses from government, said the doctor, who has headed efforts to fight the disease since September 2005.

"I've seen a huge increase in awareness of problems of highly pathogenic avian influenza, the need for a strong animal health sector, good veterinary services and an effective response in individual countries and in the regional level, particularly in this region, and globally," said Nabarro. "It's not a level where I can say everything's fine, but what I am seeing is things moving in the right direction in most countries, which is immensely gratifying because it's a sign that things are moving well together, that people are prepared to work with each other for the common good."

Nabarro was due to hold meetings Monday with Indonesian officials, UN agencies and international donors to take stock of the situation in Indonesia.

The highly pathogenic H5N1 strain of bird flu is endemic among poultry in the vast archipelago where chickens are kept in millions of homes. Most human victims had close contact with infected birds.

But improving biosecurity -- separating humans and animals, improving hygiene and making the public understand the threat of diseases leaping from birds and animals to humans -- is going to take time. "These require changes in practices that have been frankly going as they have for a very long time, so the United Nations' recommendations for transforming the way livestock are reared, will probably take several years and possibly even as much as 10 years to put into practice in this region."

Richer nations will have to provide up to one billion dollars to help tackle these problems, in particular to end raising poultry in households, a common practice among many poorer families in the region.

"Money is needed and that money has to come from the wealthier parts of the world, both governments and the private sector, because of the interdependence of the world when it comes to this kind of threat," said Nabarro who has worked in public health for three decades.

But it would be money well spent, he said.