The World Health Organisation is likely to announce that the H1N1 flu pandemic is over, indicating infection levels in most places have returned to those normal for seasonal influenza, health officials said.

Any decision to downgrade the outbreak to "post-pandemic" will be based on recommendations by influenza experts after a review earlier in the day, they said.

Japanese health ministry official Kensuke Nakajima told Reuters that the WHO is likely to decide to downgrade: "We have heard the information that they are trying to say something on the lines of it is (now) a post-pandemic period."    

Angus Nicoll, a flu specialist at the European Centre for Disease Prevention and Control (ECDC), who is not a member of the WHO's Emergency Committee, told Reuters: "The data we are seeing is consistent with such a decision of a post-pandemic period moving on to a new seasonal influenza."    

The UN agency has been heavily criticised for its handling of the first pandemic in more than 40 years, which turned out to be milder than expected in most countries. - Reuters