Japanese health officials have confirmed 72 more cases of the new strain of H1N1 influenza, making Japan the worst-affected country in the Asia-Pacific region.

Japan's Kyodo news agency said the new cases of the virus commonly known as swine flu were confirmed on Sunday in Osaka and Hyogo prefectures.

Japanese officials said most of those infected with the new swine flu virus are high school and college students in the neighboring prefectures in western Japan.

Authorities on Sunday ordered more than 1,000 schools in the affected areas to close.

Japan confirmed its first domestic infections on Saturday.

In related news, Chinese health officials on Sunday confirmed the third mainland case of the new virus, and a separate case in the Chinese territory of Hong Kong. 

China's first confirmed case, a 30-year-old student who had returned from the United States, left hospital on Sunday.  Authorities also released from quarantine 166 people who were exposed to the man.

Elsewhere in the Asia-Pacific region, Australia, Malaysia, New Zealand and South Korea have also confirmed infections of the new flu strain.

On Sunday, health officials in Chile confirmed that country's first case.

The World Health Organization says 39 countries - not including Chile - have officially reported more than 8,000 cases of the virus. The U.N. agency says most of the 72 H1N1-related deaths have occurred in Mexico.

Health experts at the World Health Organization are meeting in Geneva this week where they will discuss recommendations on the production of a swine flu vaccine.

Some information for this report was provided by AFP, AP and Reuters.