Japan will push for a greater role in Asian security at a regional summit on Friday, in a move set to anger China.
Prime Minister Shinzo Abe is expected to promote Japan as a counterbalance to China at the three-day Shangri-La Dialogue in Singapore.
The summit involves the US and Asean countries, and comes amid territorial disputes in the South China Sea between China, Vietnam and the Philippines.
Japan-China ties are also strained over disputed islands in the East China Sea.
Abe will give the keynote address at the Shangri-La Dialogue, which is also known as the Asia Security Summit, on Friday evening.
He is expected to set out a vision of Japan and its ally, the US, playing a greater role in security co-operation in Asia.
Regional defence officials, and US Defence Secretary Chuck Hagel, will be at the event.
'THREAT TO SECURITY'
Japan's top government spokesman, Yoshihide Suga, said Abe would call for "constructive discussions... towards [Asia's] peace and safety".
"Heightening situations in the South China Sea and the East China Sea" made this particularly important, Suga added.
China's delegation, led by vice Foreign Minister Fu Ying, is expected to describe Tokyo, not Beijing, as a threat to security.
China has been angered by Abe's call for a new interpretation of Japan's constitution, which bans acts of war and "the threat or use of force" to settle international disputes.
Some countries in the Association of Southeast Asian Nations (Asean) will be reluctant to antagonise China due to their economic and political ties.
However, relations with other countries have deteriorated amid increased conflict over territorial disputes.
Beijing claims a U-shaped swathe of the South China Sea that covers areas other South East Asian nations say are their territory.
On Tuesday, a Vietnamese fishing boat sank after it collided with a Chinese vessel near a controversial oil rig in the South China Sea, with both countries blaming the other for the incident.
Vietnam has protested against China moving its oil rig to waters also claimed by Hanoi, at a spot near the disputed Paracel Islands.
Meanwhile, the Philippines is in the process of taking China to a UN court over its territorial claims in the South China Sea.
Earlier this month, the Philippines arrested and then charged nine Chinese fishermen with poaching at a disputed shoal.