(Reuters)
Updated: 2005-11-14 16:01

Japan on Monday announced plans to cope with a possible outbreak of bird flu among humans, which include declaring a state of emergency, shutting down schools and banning large gatherings.

The action plan unveiled by the Health Ministry, which also set up a headquarters to deal with the issue, estimates that as much as a quarter of Japan's 127 million people could be infected and up to 640,000 could die.

The H5N1 bird flu virus cannot move easily between people, but experts fear it could mutate into one that can, setting off a pandemic that causes millions of deaths worldwide.

The plan would allow the health minister to declare a state of emergency once the disease had spread within Japan, a situation that would then allow authorities to close schools and forcibly hospitalise people who have been infected.

The ministry estimates that between 170,000 to 640,000 people could die from the disease and between 530,000 and 2 million could be put in hospital.

The plan is divided into six phases ranging from ordinary influenza to a worldwide pandemic, with the current situation -- transmission from birds to humans -- at phase three.

Japan will aim to increase its stockpile of the anti-flu drug Tamiflu to enough for 25 million people to be treated over five days rather than three days under a previous target.

Ministry officials said they hoped to carry this out by the end of the 2006 fiscal year on March 31, 2007, adding that while no budget has yet been assigned to cover the costs, they expected one would be.

Japan's Chugai Pharmaceutical Co. said on Monday it has reported to the government that two teenage boys exhibited abnormal behaviour that led to their deaths after taking Tamiflu, made by Chugai's Swiss parent Roche Holding AG

The comments came in response to weekend news reports that Japan's health ministry was investigating the deaths of two teenage boys who died in accidents linked to odd behaviour shortly after taking the drug.

Health ministry officials were not immediately available for comment.

A separate report issued on Monday by Dai-Ichi Life Research Institute Inc. said a birdflu outbreak lasting a year could reduce Japan's nominal gross domestic product by 1.4 trillion yen ($11.9 billion) or 0.27 percent.

The H5N1 bird flu virus is known to have infected 125 people in Asia, of whom 64 have died.