The Australian currency was half a cent stronger at Wednesday noon and trading near a two-year high after the greenback weakened on reports of US quantitative easing overnight.

The local unit also gained against the yen amid speculations Japan intervened to sell its currency for the first time in six years.

At midday (AEST) today, the Aussie was changing hands at US93.85c, an increase from Tuesday's finish of US93.28c. It hit US94.57c overnight, the highest since August 2008, before the global financial crisis.

Since 7am, the domestic currency has traded between US93.86c and US94.30c.

The rise had been prompted by a selloff in the greenback rather than a gain in the Aussie, according to Commonwealth Bank currency trader Joseph Capurso.

"The major move overnight was speculation by the market that the US Federal Reserve may increase their quantitative easing."

The US dollar hit a one-month low against the euro overnight and dropped to a new 15-year low versus the yen after a key election made Japanese intervention to weaken its currency less likely.

Mr Capurso predicted the Aussie would remain around its current levels until European markets opened.

"The market is now focused on unconfirmed reports that the Bank of Japan may intervene in the yen."

The dollar leaped to 78.91 yen today, compared with yesterday's close of 77.78 yen after traders spotted the Bank of Japan selling yen in the market in an effort to restrain its export-sapping strength.

Traders assumed the action was aimed at lifting the ailing US dollar, which earlier hit a 15-year low around 82.87 yen. The US dollar was at 84.08 yen by midday (AEST).