TOKYO (REUTERS) - Japanese Prime Minister Shinzo Abe sent a ritual offering to the controversial Yasukuni shrine for war dead on Thursday (Aug 15), the anniversary of Japan's World War II surrender, Kyodo News said, a gesture likely to be criticised by Asian neighbours.

Past visits by Japanese leaders to Yasukuni have outraged South Korea and China because the shrine honours 14 Japanese wartime leaders convicted as war criminals.

Protests from Seoul could be especially strong this year because bilateral relations are at their lowest level in years after a series of disputes.

Ruling Liberal Democratic Party lawmaker Tomomi Inada, a former defence minister and now special aide to Mr Abe, made the monetary offering, called a "tamagushi-ryo", on the premier's behalf, domestic media said.

Chief Cabinet Secretary Yoshihide Suga declined to comment, saying it was a private matter.

"The peace and prosperity of our country is due to those heroes who gave their lives for their homeland and I express my gratitude and respect," Ms Inada quoted Mr Abe as saying, according to domestic media.

A spokesman for the shrine could not immediately confirm the offering.

At an annual ceremony on Thursday marking Tokyo's surrender in WWII, Japan's new emperor, Naruhito, expressed deep remorse over the country's wartime past and prayed for global peace, echoing his father's words in remarks.

Emperor Naruhito, 59, became Japan's first monarch born after the war when he inherited the throne in May. His father, Akihito, stepped down in the first abdication by a Japanese emperor in two centuries.

"Looking back on the long period of post-war peace, reflecting on our past and bearing in mind the feelings of deep remorse, I earnestly hope that the ravages of war will never be repeated," he said.

"Together with all of our people, I pay my heartfelt tribute to all those who lost their lives in the war ... and pray for world peace and the further development of our country," Emperor Naruhito said, echoing his father's message a year ago.

Emperor Naruhito is a grandson of Hirohito, in whose name Japanese troops fought WWII.

Mr Abe has visited the Yasukuni in person only once since taking office in 2012 but has regularly sent offerings on Aug 15 and during the shrine's spring and autumn festivals.

China's relations with Japan have long been haunted by what Beijing sees as Tokyo's failure to atone for its occupation of parts of China before and during WWII, while bitter memories of Japan's 1910-1945 colonisation of Korea remain.

Relations between Japan and South Korea deteriorated after a ruling by South Korea's Supreme Court last year that Japanese companies should compensate South Koreans conscripted as forced labourers during WWII. Tokyo says the matter was settled by a 1965 treaty normalising ties.

The two nations this month ended each other's fast-track trade status, and Tokyo on Tuesday urged caution for travellers to South Korea ahead of crucial anniversaries this week.

South Korea celebrates Aug 15 as a national day of liberation from Japanese rule.

A steady stream of visitors paid their respects at Yasukuni under partly cloudy skies as temperatures soared. Groups including members of a tiny nationalist party and critics of the US military presence on Japan's southern Okinawa island gathered near the entrance.

Police, some in anti-riot gear, patrolled nearby. A sign inside the grounds said activities such as hoisting flags, demonstrating or destroying property were banned.

"The people enshrined here fought for Japan and we have come to express our gratitude and to show them our resolve to build a better Japan," said Ms Yoshiko Matsuura, 71, a former ward assembly member from Tokyo visiting with other local politicians.