Japanese Prime Minister Naoto Kan and Chinese Premier Wen Jiabao are already in Hanoi for an Association of South East Asian Nations Asean) summit.
Japanese broadcaster NHK reported that the pair would meet with the hope of confirming “policies of deepening their strategic, mutually beneficial relations".
Japanese Foreign Minister Seiji Maehara said Friday after a meeting with his China counterpart that the two-way summit would now "'probably take place in Hanoi".
During their meeting, Wen and Kan are expected to resume negotiations over the development of a disputed gas field in the East China Sea.
Japan has previously called for an early resumption of the stalled talks over the gas field - called Shirakaba by Japan and Chunxiao by China - which has been a casualty of the simmering territorial row.
Tokyo suspects Beijing has started drilling in the field, which lies in an area where the claims of both countries overlap.
US Secretary of State Hillary Clinton, who told an Asean security meeting in Hanoi in July that Washington is "recommitted" the region, is to arrive at the summit on Friday.