Japanese Foreign Minister Taro Aso has called for Emperor Akihito to visit a controversial war shrine - a move that could enrage China and South Korea.
Prime Minister Junichiro Koizumi has visited the shrine several times
The Yasukuni shrine, which honours 2.5m war dead, has been avoided by Japanese emperors ever since 14 top World War II criminals were enshrined there in 1978.
China cancelled a bilateral summit last month because of Prime Minister Junichiro Koizumi's repeated visits.
Mr Aso is seen as a contender to succeed Mr Koizumi when his term ends.
He believes Emperor Akihito should visit the Tokyo shrine because those who died in wars did so in honour of their emperor.
Mr Aso is reported as saying in a speech in the central Japanese city of Nagoya: "From the viewpoint of the spirits of the war dead, they hailed 'Banzai' ['long life'] for the emperor. None of them said, 'Long live the prime minister'.
"A visit by the emperor would be the best."
WWII's Emperor Hirohito, in whose name Japanese soldiers fought and died, visited the Yasukuni shrine until war criminals tried at an allied tribunal - including hanged Prime Minister Hideki Tojo - were quietly enshrined there in 1978.
His son Emperor Akihito has also refrained from praying there since he was enthroned in 1989, unlike Prime Minister Junichiro Koizumi who has prayed at Yasukuni every year since taking office in April 2001.
The move has caused relations with China and South Korea, which were invaded by imperial Japan, to become increasingly frosty.
Earlier this month, Japan and China resumed talks over energy resources in the East China Sea after a summit planned for December was called off.
But both sides failed to agree on proposals for exploring gas fields and could not resolve a row over the suicide of a Japanese diplomat.