China's purchase of a 9 per cent stake in Rio Tinto, the Australian and UK-listed mining group, may be investigated by Australia's Foreign Investment Review Board.

Kevin Rudd, Australia's prime minister, and Stephen Smith, foreign minister, who this week hosted his Chinese counterpart in Canberra, have faced repeated questioning in recent days over whether the Australian authorities will review last week's raid on the Rio share register by Chinalco and Alcoa. The Chinese state-owned mining company and the US aluminium producer spent $14bn on a 9 per cent stake in Rio.