Japan has warned its citizens in China to step up safety precautions and avoid crowded places amid a deepening dispute between Asia's two largest economies over Japanese Prime Minister Sanae Takaichi's comments on Taiwan.

Beijing has launched sweeping restrictions on travel, cultural exchanges and business visits to Japan after Tokyo signalled it might intervene militarily in a Taiwan conflict.

The cancellations amount to roughly 32 per cent of Chinese airlines' total bookings to Japan, said a veteran aviation analyst.

Mr Xi reportedly told her that China was willing to “work with Japan to…advance the strategic, mutually beneficial relationship” (with the usual finger-wagging reference to Japan’s wartime “history of aggression”).