At 12:00 (AEST), the dollar was trading at $US0.7914/18, down from yesterday's close of $US0.7943/45.
During the morning, the unit moved between $US0.7877 and $US0.7941.
The dollar touched $US0.8068 during offshore trade, but opened lower at $US0.7931/36 at 07:00 AEST after a weak finish on US equity markets boosted safe-haven US dollar buying.
The unit remained under pressure in Asian trading, as most bourses locally and around the region began the the day in the red.
Barclays Capital currency strategist David Forrester said a more mixed set of economic data in recent days had dampened expectations of how quickly global markets would emerge from recession.
"The market was squeezed into the positive global growth story. Things happened a little bit quicker than expected in terms of the data surprising to the upside," Mr Forrester said from Singapore.
"We're seeing a little bit of a reversal of that."
Mr Forrester said more recent economic data was "not all bad but not all good".
"The data is looking a little bit patchy which is hurting sentiment a little bit and probably causing some profit taking in those long risk positions,'' Mr Forrester said.
"That's probably contributing to a little bit of Aussie dollar weakness."
The US dollar was stronger in Asian trade, benefitting from the lack of any explicit discussion about an alternative reserve currency at the summit of BRIC nations - Brazil, Russia, India and China - held in the Russian city of Yekaterinburg.
Mr Forrester said domestic economic data, which showed dwelling commencements had declined for a fifth consecutive quarter, had had little impact on the Australian dollar.
