At 12.00pm (AEST), the unit was trading at $US0.7950/55, up from yesterday's close of $US0.7910/14.
During the morning session, the unit moved in a tight range between $US0.7978 and $US0.7943.
The Japanese yen firmed during the offshore session overnight, stealing investor attention from the local currency and boxing it into the tight trading range today, 4Cast financial markets head of research Ray Attrill said.
"There's been some selling pressure in the crosses, in things like euro/yen and Aussie/yen,'' he said.
"The Aussie is a touch softer today, and that has to do with the yen being a little bit firmer and it does seem like we've seen a movement out of risk.
"Things like the Aussie against the yen and (New Zealand) dollar against the yen are weaker.''
The only key piece of economic data expected today is the RBA's decision on interest rates, due at 2.30pm.
Most economists tip the cash rate to remain on hold at a 49-year low of 3 per cent.
Mr Attrill said investors would focus on the statement following the decision for clues on the RBA's thinking on the outlook for the economy. The RBA board said when it met in June that it did not
"see a pressing case for any further action at this meeting''.
"There is keen interest in what the RBA has to say today,'' Mr Attrill said.
"Whether or not they restate what they said last month, that they still see scope for (rate cuts) down the line to support growth, how they phrase that ... is what the Aussie turns on.''
Mr Attrill predicted the local unit would sell off to $US0.7900 in a "knee jerk'' reaction to any suggestion by the RBA that rates would be cut in coming months.
But if there was no suggestion of rates easing further, the unit could push towards $US0.8000 during the session, he said.
At 12.00pm, the RBA's trade weighted index (TWI) was at 63.6, steady with yesterday's close.
Meanwhile, the Australian bond market was weaker at noon.
The yield on the Commonwealth Government March 2019 bond was 5.470 per cent, up from yesterday's close of 5.438 per cent, while the yield on the April 2012 bond was at 4.357 per cent, up from 4.343 per cent.
On the Sydney Futures Exchange, the September 10-year bond futures contract price was 94.565, down from yesterday's close of 94.595, while the September three-year bond futures contract was at 95.500, down from 95.520.
