The Australian dollar is trading at a record low against the US dollar after a two-week surge to a six-month high of $US0.8098 on Monday.
In the past fortnight, the AUD/NZD exchange rate has climbed 0.7 per cent to $US2.11, its strongest level since February.
The AUD/US dollar has gained 10 per cent against a basket of currencies since the beginning of February.
The index is trading near its highest level since June 2015.
The dollar has fallen against the euro, Japanese yen, British pound, Japanese Yen, Australian dollar, Brazilian real, Singapore dollar, Singaporean dollar, South Korean won, Mexican peso, New Zealand dollar, Australian rupiah and Thai baht.
It has also fallen against other currencies, including the euro and British pound.
The currency also has retreated in Asia, as well as its trading partner the US, and has dropped 0.8 per cent in recent days.
The US dollar index was last trading at $US3.1527 on Tuesday.
Its recent rally has coincided with a spate of new releases in the US economy.
The Federal Reserve is expected to announce new policies on Wednesday aimed at boosting the US unemployment rate to 6.5 per cent, the lowest since 2009.
The Fed will also raise interest rates by the full amount of its benchmark loan rate, which it has already cut by almost one-quarter.
The latest data comes after the US central bank cut its benchmark interest rate by half in April to 0.25 per cent.
Analysts expect the Fed to increase its target for growth this year to 2 per cent from the current 1.5-1.75 per cent and also to boost the budget deficit from 2.5 percent of GDP to 3.5.
In a separate move, the Fed on Tuesday also announced a $20 billion asset purchase programme for the US energy industry.
The deal, which is expected on Wednesday, is expected the first of its kind in a major US central banking operation since 2008.
The White House is expected later on Wednesday to announce more details of the plan.