With new cases reported in Osaka and Hyogo prefectures, confirmed cases of A/H1N1 flu amounted to 290 in Japan on Thursday.

The health authorities are considering dividing the country into three areas to adopt different measures to cope with the disease, Kyodo News reported, citing government sources.

Hyogo and Osaka are likely to be designated as "an area with widespread infections," Tokyo, Kanagawa and Shiga prefectures as "an area with limited infections," and the rest of the nation as an area without an infection," it said.

Chief Cabinet Secretary Takeo Kawamura said that the government will convene a meeting Friday to deliberate a shift in measures from trying to shut the flu out of the country to curbing the domestic spread of the virus.

The spread of the new flu virus could be contained in the Tokyo metropolitan area as the two school girl patients were infected with the virus in the United States, not in Japan, said Kawamura.

During a budget committee session at the upper house, Health, Labor and Welfare Minister Yoichi Masuzoe said that the A/H1N1 influenza has been "substantially widespread" in Japan.

The government will follow the ever-changing situation and try to strike a balance between the need for anti-epidemic measures and avoiding strains on people's lives, he said.

On Wednesday, two school girls were confirmed to be infected with the new flu in Tokyo, becoming the first cases outside the Kansai region.

The Tokyo metropolitan government has instructed three high schools to keep nine students and teachers, who were in New York with the two infected girls, from attending school.

Meanwhile, the health authorities were attempting to track 17 people who had close contact with the girls on the same flight back from New York.