Japanese Prime Minister Shinzo Abe, in an apparent reference to China's growing military assertiveness, told a conference of Asian and African leaders on Wednesday that the use of force by the "mightier" should never go unchecked.

Abe also said Japan had pledged, "with feelings of deep remorse over the past war", to adhere to principles such as refraining from acts of aggression and settling international disputed by peaceful means.

It was not immediately clear if the remarks would satisfy China's desire for Japan to acknowledge its wartime past, but a Japanese official told Reuters Abe would meet Chinese President Xi Jinping on the sidelines of the Jakarta conference.

Sino-Japanese ties have chilled in recent years due to feuds over the wartime past, bitter memories of which linger in China, as well as territorial rows and regional rivalry. A meeting between the two leaders could promote an incipient thaw that began when Abe and Xi met at a summit late last year.