TOKYO: Japan's new prime minister on Sunday sent a ritual offering to the controversial Yasukuni shrine that honours the war dead but is seen by neighbouring countries as a symbol of Tokyo's past militarism.

Fumio Kishida sent the "masakaki" tree offering under his name as prime minister to celebrate the shrine's biannual festival held in the spring and autumn, a spokeswoman for the shrine told AFP. Two of Kishida's ministers also offered sacred trees.

Yasukuni honours 2.5 million war dead, mostly Japanese, who have perished since the late 19th century. But the central Tokyo shrine also honours senior military and political figures convicted of war crimes by an international tribunal.

Earlier this year, three top ministers paid their respects at the shrine on the anniversary of Japan's World War II surrender. But a Japanese prime minister has not appeared there since 2013, when Shinzo Abe sparked fury in Beijing and Seoul and earned a rare diplomatic rebuke from close ally the United States.

Kishida's predecessor Yoshihide Suga made a pilgrimage to the shrine on Sunday, the spokeswoman said, while public broadcaster NHK showed footage of his visit. Suga had avoided visiting the shrine after 2012, when he became the Abe government's spokesman, and only sent ritual offerings when he became prime minister.

Visits to the shrine by government officials have long angered countries that suffered at the hands of the Japanese military prior to and during World War II, particularly South Korea and China.

Kishida, who became Japan's prime minister on October 4, does not plan to visit the shrine during the two-day autumn festival that runs through Monday, Kyodo News reported, citing unnamed people close to him. But Seoul's foreign ministry Sunday expressed "deep disappointment" at his decision to send an offering.

"The government expresses and regrets that Japanese leaders again sent the offering or repeated their visits to the Yasukuni shrine," it said in a statement, according to South Korea's Yonhap News Agency.

Seoul urged Tokyo's leaders to "squarely face history and show by action their humble introspection on and genuine self-reflection for the past history".