Asian markets headed into the weekend on a sour note as a warning from Federal Reserve chairman Ben Bernanke that some small US banks could collapse refreshed fears about the state of the US economy.

Crude oil, palm oil and gold hit fresh life-time highs and the dollar sagged, with the yen climbing to its highest point against the greenback in nearly three years. The yen also rose against the Australian and New Zealand dollars, two of the currencies favoured by carry traders who borrow cheaply in Japan to invest the money in much higher-yielding assets abroad.