TOKYO - JAPANESE Emperor Akihito and Empress Michiko will visit Pearl Harbor this summer, the site of Japan's surprise attack on the United States during World War II, a news report said on Sunday.

If realised, it would be the first visit by the royal couple to the spot where the Japanese bombardment of the US fleet heralded the declaration of war between the two countries.

Emperor Akihito is the son of war-time Emperor Hirohito, under whom the Japanese military carried out the December 1941 attack in Hawaii, which killed around 2,500 people, mostly American soldiers.

The visit would be made on the way back to Japan from the couple's planned official trip to Canada this summer, Kyodo said.

Under the plan, the emperor and empress will 'unofficially' stop over in Hawaii to meet with local Japanese-American groups and visit Pearl Harbor during a break, Kyodo said.

Lower house speaker Yohei Kono, widely known for his dovish policies, visited Pearl Harbor in December last year, making him the highest-ranking Japanese official to do so.

Mr Kono made the visit after US House of Representatives speaker Nancy Pelosi last year visited Hiroshima, a site of the first US atomic attack in 1945, becoming the most senior ranking sitting US official to do so. -- AFP