The share market has given up its early morning gains due to a sell-off among mining and energy stocks and a plunge by building products maker Boral.
The benchmark S&P/ASX 200 index was down 0.15 per cent at 1200 AEDT.
CommSec senior manager Juliana Roadley said there was weakness across the board, but particularly among energy and resource stocks.
Boral had plunged 11.7 per cent after the building materials supplier completed an institutional capital raising to help fund its $US2.6 billion ($A3.5 billion) acquisition of US firm Headwaters.
"Boral has taken quiet a few points off the index," Ms Roadley said.
"Gold stocks are down because of a steep fall in gold prices and then we have the three major oil companies in the red.
"There's not much around to drive growth today."
Gold miner Newcrest Mining had tumbled 3.4 per cent, while Oil Search was the weakest of the oil producers, down 2.1 per cent.
Rio Tinto was down nearly one per cent after agreeing to sell its Scottish aluminium assets for $410 million to commodities group SIMEC, while BHP Billiton was 0.15 per cent lower.
Telstra had dropped two cents to $4.98, while the big four banks were modestly higher, with gains of between 0.3 per cent and 0.7 per cent.
* At 1200 AEDT on Thursday, the benchmark S&P/ASX 200 index was down 8.2 points, or 0.15 per cent, at 5,476.2.
* The broader All Ordinaries index was down 8.4 points, or 0.15 per cent, at 5,541.5.
* The December share price index futures contract was down 16 points at 5,480 points, with 15,942 contracts traded.
* National turnover was 1.2 billion securities traded, worth $1.6 billion.