The Australian currency opened weaker today after soft US and Italian economic data dampened investor sentiment for risk.

At 7am (AEST), the local unit was trading at $US0.8933/35, a decline from Friday's finish of $US0.9025/28.

Since 5pm Friday, the domestic dollar ranged from $US0.9034 to $US0.8922.

The unit plunged after equity markets reacted badly to US retail trade data on Friday and a poor auction of Italian bonds, according to Bank of New Zealand currency strategist Mike Jones.

"The Aussie dollar played hostage to equity markets on Friday and the weaker sentiment knocked it lower," he said.

While the US Commerce Department announced, during Friday's offshore session, that retail sales were up 0.4 per cent in July after two months of slump, the improvement was below the 0.5 per cent increase expected by most analysts.

The poor result depressed the mood for risk on US equity markets, which finished lower.

The Dow Jones Industrial Average declined 0.16 per cent at 10,303.15 points, and the broader S&P 500 index lost 0.40 per cent to 1079.25 points.

Italy, likewise, suffered a lower-than-expected bond auction that also weakened risk appetite. Although the auction of 15-year government bonds collected bids worth 1.27 times the amount on offer, the figure reflects a decline from the bid-to-cover ratio of 1.74 the last time that bond was on offer in May.

"The Aussie traded lower with those trends," Mr Jones said.

He predicted the Aussie to trade between $US0.8900 and $US0.8980 today (AEST).