The Australian share market is trading at a fresh 19-month high, after commodity prices were boosted by the US budget deal.

The All Ordinaries index was up 22 points to 4,745 just before 11:00am (AEDT), and the ASX 200 index was up 20 points to 4,726.

Fortescue Metals was up 1.8 per cent and Rio Tinto had jumped 1.3 per cent.

Smaller miner Aquarius Platinum was trading 15 per cent stronger.

Shares in Qantas had risen 3.5 per cent.

Fairfax was also up sharply, by close to 4 per cent to 53.5 cents.

The major banks have added between 0.2 and 0.4 per cent each.

The Australian dollar has come off its overnight high against the greenback and was buying 104.89 US cents.