The Australian dollar has closed below 104 US cents for the first time since November as investors poured into the US dollar amid ongoing US budget talks.
At 1700 AEDT on Thursday, the local unit was trading at 103.57 US cents, down half a per cent from the pre-Christmas close of 104.09 US cents on Monday.
It was the Australian dollar's weakest close since November 21, when the currency finished the domestic trading day at 103.56 US cents.
During the day, it moved between 103.79 US cents and 103.46 US cents.
The Australian dollar opened the first local session since the two-day Christmas and Boxing Day break at 103.71 US cents and remained under pressure throughout the day.
Easy Forex currency dealer Tony Darvall said the move in the Australian dollar was due to traders returning to the safe haven asset of the US dollar.
"There are US fiscal cliff concerns that are US dollar positive, at the moment anyway," Mr Darvall said.
However, he said the Australian dollar was not likely to fall significantly, in part due to its strength against Japanese yen.
The local currency peaked at a two-week high against the yen, and the US dollar hit its highest level against the Japanese currency since September 2010.
"The Aussie-yen cross rate is a big part of the Australian dollar's support structure," Mr Darvall said.
"You can't get a steep sell in the Aussie dollar if the Aussie rallies against the yen.
"This type of gentle selling in the past three or four days is the type of selling that leads to buying.
"You could definitely see a return to Aussie buying."
US President Barack Obama cut short his Christmas holidays in Hawaii to return to Washington for talks with US Congressional leaders on the US fiscal cliff - tax hikes and spending cuts due to start in early 2013.
If they are unsuccessful in finding a solution, the measures were expected to push the US back into recession.
"Obama would not have headed back early if he didn't have the numbers, possibly to do a compromise bill, so it could be bad news as well as good news," Mr Darvall said.
