Asian Development Bank president Haruhiko Kuroda said Thursday any Asian currency integration is a long way off and cast doubt on the Chinese yuan emerging as a regional unit. The idea of a single currency for Asia and of integrating the region\'s economies was first touted after the financial crisis of 1997-1998. But the recent problems seen in the eurozone, with the bailouts of countries like Greece and Ireland, have exposed the frailties of a common currency area. In an interview with the Australian Financial Review, Kuroda said an Asian integration may happen, but not yet. He added that he did not think the yuan or the Japanese yen would emerge as a single Asian currency or take on the role of the US dollar in the region. \"In 40, 50, or 60 years\' time there could be a common currency in some parts of east Asia or even broader than that,\" he told the newspaper. \"I tend to think that in Asia neither the yen or the yuan or any national currency will become so widely used (as the US dollar). \"If ever Asia has a common currency it would be what you call an artificial or agreed currency like the euro,\" he added. The Manila-based development lender has previously backed an Asian currency but has focused more recently on trade and investment integration. Kuroda has been in Australia for meetings with Prime Minister Julia Gillard and Reserve Bank governor Glenn Stevens.