The Australian dollar jumped after business confidence data showed an unexpected improvement, and analysts tipped the currency could receive a boost from Japan's moves to unleash its $1.3 billion pension vault on global markets.

A National Australia Bank survey found business confidence bumped up one point last month, despite the federal government's tough budget in May and weak consumer confidence.

The Aussie dollar jumped just shy of US94¢ immediately after the release of the data, and hovered just beneath for most of the day. In the afternoon session on Tuesday it was trading at US93.85¢.

Business confidence has been steadily rising since January, with conditions improving for all industries. The construction sector surged and service industries remained the best performer. Manufacturing and wholesale were weakest.

NAB warned that conditions are still ''below the long-run average for the monthly series, which along with soft conditions in wholesale, suggests little momentum for domestic demand in the near term''.

The Aussie dollar touched a high of US93.97¢ but there appeared to be very little buying momentum.

''I suspect there were some who had positioned themselves short ahead of this number, given that we rose to the top over the overnight range,'' CMC Markets chief markets strategist Michael McCarthy said.

''The spike we saw was actually a scramble to short cover rather than any bullish expression.''

Perhaps to the distress of the Reserve Bank, the Aussie may strengthen further over coming months as Japanese Prime Minister Shinzo Abe's transforms the asset allocation of Japan's $1.3 trillion Government Pension Investment Fund.

Mr Abe is looking to dramatically reduce the fund's weighting in Japanese government bonds and look towards offshore equities, bonds and infrastructure.

''That pension fund has been heavily invested in Japanese government bonds and got sod all for its money,'' said Rochford Capital's Thomas Averill, who argues Japanese offshore investment will result in more change to the AUD/Yen cross than the AUD/US cross.

''I think you'll see the Japanese try to buy US debt as well,'' he said.

China trade balance numbers are due to be released on Thursday and analysts believe that will affect the dollar more than the release of the US Federal Open Market Committee minutes.

In a note to clients on Monday, Goldman Sachs brought forward its forecast for the Federal Reserve to raise interest rates in the third quarter of 2015 rather than the beginning of 2016.

''The market is already pricing in what Goldman has said, so it's hard to see a huge reaction to the minutes,'' Mr McCarthy said.

''More important for the Aussie is China's trade numbers shining light on the trade flows and the potential for further trade flows.''