Past visits by top leaders to Yasukuni, which honours even convicted war criminals, have infuriated China and South Korea, and no Japanese premier has visited since 2013.

It is common however for prime ministers to send offerings for its biannual spring and autumn festivals.

Sanae Takaichi made an offering on Friday morning, the first day of the autumn festival, an official from her office told AFP.

Yasukuni in central Tokyo is dedicated to 2.5 million war dead, mostly Japanese, who have perished in conflicts since the late 19th century.

But this includes senior military and political figures convicted by an international tribunal of war crimes prior to and during World War II.

The conservative Takaichi, who was elected as the head of the ruling Liberal Democratic Party (LDP) earlier this month, has visited on many occasions, including as a minister.

However, she is unlikely to this autumn festival, local media reported, with business daily Nikkei saying she was concerned about the "impact on diplomacy".

A visit to the shrine in 2013 by then-prime minister Shinzo Abe, Takaichi's mentor, prompted fury from China and South Korea and disquiet from Washington.

Abe's three successors including outgoing premier Shigeru Ishiba stayed away from the site during their terms at the top.

Takaichi had seemed a shoo-in to replace Ishiba. But after the Komeito party, the LDP's junior partner, left the ruling coalition last week, she is now in a race to find new partners that could help her become the nation's first woman prime minister.