At 1700 AEDT, the Australian dollar was trading at US$0.9134 37, down from Thursday's close of US$0.9208/10.
Since 0700 AEDT, the local unit traded between US$0.9183 and US$0.9130.
4Cast financial markets head of research Ray Attrill said the local dollar was subdued throughout much of Friday's domestic session.
"The Aussie has been pretty soft today for not any other obvious reason than the US dollar has been pretty well bid all day," he said.
"Together with a somewhat firmer US dollar ahead of the pay roll (employment) figures tonight ... is why the Aussie has been languishing today."
The US dollar strangulated against the yen overnight after Japanese Finance Minister Naoto Kan said in his inaugural press conference in Tokyo that he would like the currency to weaken a bit more after its nine per cent drop from a 14-year high in November.
In turn, investors fled risk sensitive currencies like the Australian dollar.
The local unit was also restrained by thin trading volume during the domestic session.
Mr Attrill said investors were waiting for key US employment data due during Friday's offshore session.
The US Department of Labor is expected to publish its monthly nonfarm payrolls report for December.
The key measure of US employment fell by 11,000 in November, the smallest amount of job losses since the start of the US recession in December 2007, the Labor Department said last month.
The median market expectation is for US employment to be flat in the month.
Mr Attrill said a better than inspected figure could incite investors to buy more US dollars, further weakening the Australian unit.