The S&P/ASX200 dropped at the open the climbed into the green in the first half an hour of trading, but only briefly.
At noon AEST on Tuesday, the benchmark was down 14.5 points, or 0.19 per cent, to 7,736.9, while the broader All Ordinaries had dropped 14.4 points, or 0.18 per cent, to 7,977.9.
Traders were looking through the minutes of the Reserve Bank's June 18 meeting for clues on what the board would need to raise rates, with the futures market currently implying one-in-three odds of a hike at the board's August 6 meeting.
The minutes released on Tuesday said it was "difficult either to rule in or rule out future changes in the cash rate target", and board members would pay careful attention to the global economy.
Six of the ASX's 11 sectors were lower at midday, four were flat and telecommunications was basically flat.
Energy was the biggest mover, up 1.4 per cent as Brent crude changed hands near a two-month high of $US86 a barrel.
Woodside gained 2.3 per cent to $28.89, Santos added 0.7 per cent to $7.685 and Whitehaven Coal rose 3.1 per cent to a five-month high of $8.385.
The Big Four banks were all lower with NAB down 1.0 per cent, Westpac and CBA both dropping 0.5 per cent and ANZ dipping 0.3 per cent.
In the heavyweight mining sector, BHP and Rio Tinto were down 0.5 per cent, while Fortescue had fallen 0.8 per cent. IGO was five per cent lower and Mineral Resources had dropped 2.6 per cent.
RPMGlobal Holdings had dropped 17 per cent to a two-and-a-half month low of $2.30 as the mining software solutions company said it expected to post $14 million to $14.5 million in 2023/24 profit, less than previous forecasts.
One Australian dollar was buying 66.43 US cents, from 66.74 US cents on Monday.