The Australian dollar has been dragged nearly a US cent lower by a fall in commodity prices and a stronger American currency, boosted by high US Treasuries yields.
At 0630 AEST, the local unit was trading at 91.15 US cents, down from 92.04 cents on Monday.
The Australian dollar dropped almost one US cent overnight following a fall in commodities in overseas markets.
In metals trading, most futures contracts fell.
Gold, silver and copper ended lower as did the price of oil.