The WHO recommended Monday that making seasonal flu vaccines was still the priority, advising the pharmaceutical industry against switching its production focus onto the new swine flu virus.
"WHO made the recommendation that seasonal influenza vaccine (production) should continue," World Health Organisation chief Margaret Chan told member states at an annual assembly in Geneva.
"We are taking double insurance, I want to make sure countries get sufficient supplies of seasonal influenza vaccine."
Chan said the industry was still not in a position to make a potential swine flu vaccine.
The swine flu virus that emerged in Mexico one month ago has pandemic potential according to the WHO, which has placed the world on flu alert level five, one short of a pandemic of global sperad of the virus.
"We need to balance the risk coming from seasonal influenza and also continue to track the new virus," Chan explained.
She pointed out that health ministers could face a situation where they would have to explain why more people were dying from seasonal influenza than the new virus.
Based on experience gleaned from the 40 countries where outbreaks of swine flu have spread, health experts say the symptoms of A(H1N1) are regarded as no more severe than those of seasonal flu.
UN Secretary General Ban Ki-moon was set to meet pharmaceutical companies here on Tuesday to discuss production of a pandemic flu vaccine, which could take up to six months to develop.
The WHO has to weigh the risks involved in halting seasonal flu vaccine output in order to free up production capacity for large scale pandemic vaccine production.