Amid a growing row with China over its new air defence zone, Japanese Prime Minister Shinzo Abe is hoping to use a summit this weekend to win ASEAN leaders over to his side.
Japan and ASEAN are "partners to each other in terms of (keeping) the Asian seas and oceans free and open", Mr Abe said on Thursday, ahead of the summit marking 40 years of ASEAN-Japan ties.
In an interview with ASEAN journalists, Mr Abe named freedom of the sea as one of the regional and global issues he hopes to discuss with ASEAN leaders.
But the 10 ASEAN countries are likely to tread cautiously between the rowing neighbours.
Beijing on Thursday warned that Japan "should not target or hurt the interests of a third party when developing relations with others".
Instead, it should do its part for regional peace and stability, said a Foreign Ministry spokesman at a routine press briefing.
Mr Abe had strong words regarding China's decision last month to declare an air defence identification zone (ADIZ) over the East China Sea, dialling up tensions in the region. "(The establishment of the ADIZ) constitutes a dangerous act that unilaterally changed the status quo in the East China Sea, escalating the situation, and that may cause unintended consequences," he said.
He cautioned that China, by issuing vague warnings that it will carry out "defensive emergency procedures" against planes that do not abide by its instructions in the ADIZ, "unduly infringes" the principle in international law prescribing freedom of flight in international airspace.
Furthermore, the disputed Diaoyu/Senkaku isles appear to be part of China's territorial airspace on the ADIZ map. Said Mr Abe: "Japan can never accept nor tolerate it." His country is determined to "defend resolutely our territorial land, sea and air space".