The Australian share market has tumbled more than one per cent amid concerns about a continued fall in commodities and a weak lead from Wall Street.

Iron ore prices in China plunged to a fresh six-year low overnight, falling more than 10 per cent to $US44.59 a tonne.

The soft opening on the local market comes after a bruising session for US stocks, with all 30 members of the blue-chip Dow Jones index falling.

IG Markets chief market strategist Chris Weston said concerns about falling commodity prices, such as iron ore, were a major contributor to anxiety on the Australian market on Thursday.

“Traders are waiting for direction from what happens in China today, while there’s also interest in unemployment figures to be announced”, he said.

Among the iron ore miners, BHP Billiton was down 24 cents, or 0.94 per cent, at $25.19 by 1028 AEST, while Rio Tinto had dumped 63 cents, or 1.26 per cent, to $49.43.

Fortescue Metals Group had lost six cents, or 3.58 per cent, to $1.615.

As for the big four banks, ANZ had shed 47 cents to $31.80, Commonwealth had fallen $1.13 to $84.64, National Australia Bank was down 41 cents to $32.92 and Westpac was 54 cents lower at $32.62.

In company news, Alumina shares lifted half a cent to $1.43 after announcing it received $US71 million in income in the first half of the year.

Meanwhile, Caltex fell 62 cents to $32.75 despite reporting a 45.1 per cent increase in its unaudited first half net profit to $251 million.

KEY FACTS

* At 1028 AEST on Thursday, the benchmark S&P/ASX200 index was down 64.5 points, or 1.18 per cent, at 5,405 points.

* The broader All Ordinaries index was down 64.1 points, or 1.17 per cent, at 5,392.4 points.

* The September share price index futures contract was down 50 points at 5,351 points, with 11,071 contracts traded.

* National turnover was 297.5 million securities worth $691.9 million.