Japan should act as a "thought leader" in Asia, using experience learned over decades of postwar development to help neighbouring countries deal with issues of nationalism, environmental degradation and an ageing society, Taro Aso, foreign minister, said yesterday.

Speaking on the eve of the inaugural East Asia summit in Malaysia, Mr Aso, considered a potential successor to Junichiro Koizumi as prime minister, sought to soften his image as a hardliner by apologising to Japan's neighbours for his country's wartime conduct.