At midday AEDT, the dollar was trading at $US0.9265/68, up from yesterday's close of $US0.9282/84.
Since 7am AEDT, the unit has moved between $US0.9257 and $US0.9296.
Wall Street rallied overnight following mostly positive third quarter corporate earnings.
The Dow Jones Industrial Average closed up 1.33 per cent.
The Dow Jones had closed weaker the previous two days.
The broad-market Standard & Poor's 500 index ended up 1.06 per cent, while the Nasdaq composite was 0.68 per cent higher.
Westpac senior currency strategist, Sean Callow, said the Australian dollar continued to strengthen as it followed the fortunes of US equities.
"It rallied when US equity markets rallied in their afternoon trade," Mr Callow said.
"The US stock market is still the overall barometer for risk appetite and we got a lot of good earnings news overnight.
"That encouraged risk appetite and pulled the Aussie (dollar) higher as a result."
Mr Callow said the currency lost some of its gains during trade morning in thin conditions.
"The traders are complaining that liquidity is thin," he said.
"The data calendar is not very inspirational locally."
For the rest of the Asian session today, Mr Callow forecasts the dollar to trade between $US0.9250 and $US0.9300.
Shares open higher in morning tradeStocks appear headed to sharply higher opening
