The Australian dollar opened steady today as investors wait for the release of official inflation data.

At 7am AEST, the local unit was trading at $US0.9022/28, a minimal increase from Tuesday's close of $US0.9021/23.

Since 5pm AEST yesterday, the Aussie ranged between $US0.9000 and $US0.9069, its highest level from May 10 until now.

Wall Street finished mixed after three days of strong gains following a report that suggested a fall in US consumer confidence.

The US Conference Board's revealed that its consumer confidence index plunged from June's revised reading of 54.3 to 50.4 points.

The Dow Jones industrial average ended up 0.12 per cent, while the Standard & Poor's 500 index slumped 0.1 per cent.

The Australian currency traded in a tight range in following the movements on US equity markets, according to Commonwealth Bank vice-president of institutional banking and markets, Tim Kelleher.

"The crosses have not moved that far, so it is mainly against the US dollar."

He said investors were expecting the consumer price index (CPI) report for the June quarter on Wednesday at 1130 AEST for a further pointer on interest rates.

A high inflation reading could pressure the central bank to increase the overnight cash rate a quarter of a percentage point to 4.75 per cent on Tuesday, August 3.

The Reserve Bank uses monetary policy to limit inflation within its target band of 2 to 3 per cent over the economic cycle.

"The RBA obviously mentioned that in the minutes the other week," he said.

"It (the CPI number) has everyone's focus."

Mr Kelleher predict the local currency to trade between $US0.9000 and $US0.9050 ahead of the release of the CPI news.

He said the Aussie could reach $US0.9100 to $US0.9150 if the inflation report pointed to a possible rate hike.