TOKYO - Japan has eased quarantine and immigration measures aimed at controlling the spread of swine flu, saying the virus was not as virulent as first feared.

The government also downgraded an earlier warning against non-essential travel to Mexico, the worst-hit nation, instead urging caution when visiting the country.

The number of confirmed A(H1N1) infections in Japan has risen to 299, but there have been no fatalities and most cases have been mild, health officials said.

"The new influenza has strong similarities to seasonal flu," Health Minister Yoichi Masuzoe told reporters.

The new virus is highly contagious but many people recover without falling seriously ill and anti-flu drugs have proven effective, he said.

Japan will end on-board quarantine checks for flights from Mexico and North America unless advance notice is given that some passengers appear ill. Also, people seated close to an infected passenger will no longer be quarantined.

The government has scrapped tighter visa rules for Mexicans, allowing them to get visas on arrival again.

In the worst-affected prefectures of Osaka and Hyogo in western Japan, people who have a fever after returning from overseas can now go to regular hospitals and not just special "fever clinics" set up to contain the new flu.

More than 4,800 schools and kindergartens, mostly in western Japan, remained closed to slow the spread of the virus, the education ministry said.

Japan stepped up health controls at its airports and booked 500 hotel rooms near Tokyo's Narita International Airport in late April due to fears of a pandemic. It also told its own nationals to consider leaving Mexico.

The swine flu virus has claimed 85 lives worldwide with more than 11,000 infections confirmed, according to the World Health Organization.

The latest confirmed cases in Japan include a South Korean who arrived from the United States. He had been due to continue to South Korea but is now quarantined near Narita airport, the health ministry said.