The Australian currency finished at two-year high on Friday, returning to heights held before the financial crisis.

At 5pm AEST, the Aussie was changing hands at 94.39 US cents, an increase from Thursday's finish of 93.55 cents.

This was the strongest close on a domestic session since July 31, 2008, when the local unit ended at 94.54 US cents.

It was also the local unit's second visit above 94 US cents this week, after it had jumped as far as $US0.9457 offshore on Tuesday.

The Aussie broke through two key psychological levels - 93.70 US cents and 94.20 cents - before appreciating further, and faster, against a weak greenback, according to CMC Markets foreign exchange dealer Tim Waterer.

''There wasn't any news out during the Asian session, but we have just seen a lot of US dollar selling,'' he said. ''When it got to those psychological levels, it shot up another 10 to 20 pips quite quickly.''

Mr Waterer said the domestic currency was backed by strong commodity prices, especially gold, and a strong performance on the Australian bourse.

During the offshore session the US Department of Labor is expected to publish its consumer price index (CPI) for August.

Analysts predict the official measure of US inflation will show prices up 0.3 per cent in the month, at the same pace as July. The rate of inflation is forecast to be at 1.1 per cent in the year to August.