Kuwait is planning to “double or triple” its investment in Japan, in a move that could take its total commitment to $50bn, according to Mustapha al-Shamali, the Gulf state’s finance minister.

Both Mr Shamali and Bader al-Saad, head of the Kuwait Investment Authority, have been on a visit to Asia with Sheikh Nasser al-Mohammad al-Sabah, the Kuwaiti prime minister.