While Japan has yet to see a confirmed case of swine flu, experts believe it won't be long before someone will be infected.

They say that although caution over the new H1N1 virus is necessary, the nation should remain calm and assess new information carefully.

"Some people seem to have the impression that a killer virus is coming, but it's not a killer virus. It's true however that it could spread" once someone catches the new flu, said Nobuhiko Okabe, director of the Infectious Disease Surveillance Center in Tokyo, part of the National Institute of Infectious Diseases.