At 12.00pm AEST, the benchmark S&P/ASX200 was down 34.6 points, 0.92 per cent to 3722 and the broader All Ordinaries was down 35.6 points, or 0.96 per cent, to 3660.8.
On the Sydney Futures Exchange, the June share price index contract was 31 points lower at 3733 on a volume of 12,905 contracts at 1200 AEST.
CMC Markets analyst David Taylor said the market had pulled-back after a good run in recent days, with banking and mining stocks hit hard.
"The market is just in a bit of a consolidation phase at the moment and the likes of the normal safe sectors and defensive sectors, like consumer staples, are doing well, and the healthcare sector is doing well," Mr Taylor said.
"That is a sign that investors are perhaps more nervous than they have been in the past and money is flowing away from the mining and banking stocks," he said.
Rio Tinto shares at 12.00pm AEST were down 8.8 per cent, or $5.20, to $53.90, while BHP Billiton fell $1.09 to $32.91.
Earlier on Tuesday, Rio Tinto announced its Alcan arm would cut back an expansion project and reduce bauxite production.
The move will result in the loss of 135 full time jobs and about 570 contractor positions.
The market opened in the red after commodity and Wall Street prices fell overnight, with the Dow Jones Industrial Average falling 41.74 points to 7975.85, a fall of 0.52 per cent.
Share market gains ground
