TOKYO (AFP) - Tokyo on Tuesday (Oct27) said a long-awaited leadership summit with Seoul had yet to be set, as local media reported that behind-the-scenes bickering over Japan's wartime sex slavery was a key sticking point.

On Monday, a spokesman for the South Korean presidential Blue House said Seoul had proposed a summit between Japanese Prime Minister Shinzo Abe and President Park Geun Hye on the sidelines of a trilateral leadership meeting being held with China in Seoul next week.

Tokyo did not immediately comment on Monday evening and Japan's top government spokesman was vague on the issue at a Tuesday press briefing, less than a week before the proposed Nov 2 meeting.

"On the Japan-South Korea (summit), I think we are still in the process of coordinating," Yoshihide Suga told reporters.

"It's always the case, isn't it? (These things) are always decided right before the meeting".

The proposed talks would be the first one-on-one summit between Abe and Park, who has repeatedly refused to have such a meeting since taking office in February 2013, arguing that Tokyo has yet to properly atone for its past actions.

Relations between the neighbours have never been easy - clouded by sensitive historical disputes related to Japan's 1910-45 colonial rule over the Korean peninsula and, in particular, the issue of Korean "comfort women" forcibly recruited to work in Japanese wartime military brothels.

The rift has frustrated Washington, which would prefer its two key Asian allies to focus together on containing an increasingly assertive China.

Park had initially signalled her willingness to meet Abe during a recent visit to Washington but stressed that in order for the summit to be "meaningful" there would have to be timely progress on the comfort women issue.

Japan maintains that the issue was settled in a 1965 normalisation agreement, which saw Tokyo make a total payment of US$800 million (S$1.1 billion) in grants or loans to its former colony.

Japan's top-selling Yomiuri daily and the Mainchi newspaper said the two sides were still squabbling over the hot-button military brothel issue.

Tokyo and Seoul "are seemingly still working to fill the gap over how to deal with the comfort women issue", the Yomiuri said, citing unnamed diplomatic sources.

The paper added that the meeting was still likely to happen.

The leading Nikkei business daily and some other Japanese media, however, said the holdup was mainly due to scheduling conflicts, including the timing of Abe's meeting with Premier Li Keqiang, who will represent China at the gathering in Seoul and will hold a separate one-on-one meeting with Park.

The last summit was in December 2011 between the then-South Korean and Japanese leaders Lee Myung-Bak and Yoshihiko Noda.

The trilateral leadership meetings with China were initiated in 2008 and held annually until 2012 when they were suspended after Seoul-Tokyo relations went into one of their regular tailspins.