Governments should invest in vaccines for all strains of influenza virus that exist in the animal kingdom as an insurance policy in case of an outbreak in humans, the incoming chief scientist at the World Health Organization said on Monday.

Countries ranging from the United States and Britain to France and Japan have suffered record losses of poultry in outbreaks of avian flu in the past year.

The recent spread to mammals of H5N1 - commonly known as bird flu – needed to be monitored, but the risk to humans remained low, the WHO said earlier this month.

Incoming WHO chief scientist Jeremy Farrar said he would like to see the pharmaceutical industry at least conduct some clinical trials for all influenza strains such that the world would not have to start from scratch to initiate global manufacturing should the need arise.

"My concern that we're in slow motion watching something which may never happen," he added in a media briefing. "But if it were to happen, would we look back on what we're doing at the moment and say, why didn't we do more?"

Farrar is a clinical scientist who most recently served as the director of the Wellcome Trust. He was appointed as the WHO's chief scientist in December, and will formally join the agency later this year.