At 12.01pm (AEST), the benchmark S&P/ASX200 index was down 26.7 points, or 0.6 per cent, at 4399.4 points, while the broader All Ordinaries index had fallen 23.9 points, or 0.54 per cent, to 4410.3 points.
Austock Securities senior client adviser Michael Heffernan said the market had waxed and waned throughout the day.
"The big news today is Woolworths announcement of taking over (hardware wholesaler) Danks, and having the joint venture with Lowes in the US,'' he said.
Consumer staples were mixed after supermarket giant Woolworths announced it is to enter the hardware sector with a takeover offer for Australia's second largest hardware wholesaler, Danks Holdings.
Woolworths was up 2.25 per cent at $28.64 while rival Wesfarmers fell 6.92 per cent to $24.49.
The major miners were in negative territory.
BHP Billiton was down 17 cents at $38.01 while rival Rio Tinto had fallen 31 cents to $58.67.
"When you wake up in the morning and you hear that the Dow Jones is either up or down by less than one per cent, you know you are going to have a reasonable day,'' Mr Heffernan said.
The major banks were also mixed.
Commonwealth Bank was down 17 cents at $44.44 while NAB added 32 cents to $27.00, ANZ was up 5 cents at $19.86, and Westpac lost 30 cents to $23.43.
Energy stocks were mixed after Australia's third largest oil and gas company, Oil Search, announced that first half profit down 73.3 per cent, as weaker prices and lower sales took their toll.
The Oil Search result followed the price of crude oil continuing to rise overnight, this time by 48 US cents to $US74.37.
At 12.13pm, Oil Search shares were up 4.83 per cent at $6.08. Woodside Petroleum lost 88 cents to $48.20, and Santos fell 18 cents to $15.44.
Of the gold miners, Newcrest fell 46 cents to $28.88, Newmont Mining lost 17 cents to $4.75 and Lihir Gold increased 8 cents to $2.57.
The spot price of gold was $US944.55 per fine ounce at 12.20pm, down $US9.00 on yesterday's close of $US953.55 per ounce.
On Wall Street, the Dow Jones Industrial Average rose 3.32 points, or 0.03 per cent, to 9509.28 points.
The tech-heavy Nasdaq composite lost 2.92 points, or 0.14 per cent, to 2017.98, while the broad-market Standard & Poor's 500 index fell 0.56 point, or 0.06 per cent, to 1025.57.
On the Sydney Futures Exchange, the September share price index contract was 39 points lower at 4380 on volume of 12,836 contracts.
Stocks tumble amid investors’ worriesResources push shares lower at noon
