The Australian dollar opened more than half a US cent stronger as equity markets rallied and commodity prices surged overnight.

At 7am AEST on Tuesday, the local unit was trading at $US0.9136/39, an increase of 0.54 per cent from yesterday's local end of $US0.9087/90.

Since 5pm AEST, the domestic currency ranged from $US0.9092 to $US0.9143, based on IRESS data.

Bank of New Zealand currency strategist Mike Jones said the Australian dollar climbed as it followed leads on equity markets and soaring commodity prices.

"Risk appetite generally remained fairly buoyant so all in all it was a very positive backdrop for the Australian dollar, so it was no surprise that we saw it strengthen," Mr Jones said.

US stock markets jumped overnight as sentiment was propped up by better-than-expected results from European banks and positive US data.

Oil prices hit $US81 on Monday, striking levels last occurring in May.

Analysts are expecting the Reserve Bank of Australia will leave its cash rate on hold when it announces its August interest rate ruling at 2:30pm today.

"There's enough caution about the Australian economic recovery to keep rates unchanged, but I do think markets will be interested in the tone of the RBA's accompanying statement," Mr Jones said.

With interest rate markets pricing out any further cash interest rate hikes this year, investors would look to the statement for "any signs of tightening bias," he said.

"If that's found I think we may see a bit more support for the Australian dollar."

He said the announcement of local retail sales and building approvals results on Tuesday morning would be significant pointers of the underlining strength of the local economy.

Mr Jones predicts further strength in the Australian dollar during morning trade.