The Australian stock market was lower at noon, dragged by the banking and mining sectors, which both experienced losses.

At midday east-coast time, the benchmark S&P/ASX200 Index hit 4487.9 points, down by 52.8 points or 1.16 per cent. The broader All Ordinaries Index had slumped 51.7 points or 1.13 per cent to 4511.3 points.

On a sector-by-sector basis, health was the only sub-index to gain, up 0.43 per cent. The worst performer was information technology, shedding 8.13 per cent. Financials and consumer discretionary followed with 1.31 and 0.76 per cent decline, respectively.

On the Sydney Futures Exchange by noon, the September share price index contract lost 53 points at 4454 points, with 19,606 contracts traded.

Bell Potter senior adviser Stuart Smith said the approaching election was the main reason why the local market was lower.

According to him, the other factors pulling the market down were data on weakening business confidence and a slowdown in imports into China, which is Australia's main export target.

Mr Smith said uncertainty created by the election may be the reason for the market's reaction to Commonwealth Bank's profit result.

Shares in CBA lost $1.12 or 2.12 per cent at $51.63 even after Australia's biggest bank announced it gained 20 per cent in full-year profit and would retain conservative capital and liquidity settings given the uncertain environment.

Stocks across the financials sector plunged.

Westpac shed 63 cents, or 2.71 per cent, to $22.65, National Australia Bank slumped 21 cents at $24.29 and ANZ edged down 27 cents to $22.36.

Mining stocks were also weaker, with BHP Billiton losing 39 cents to $40.34, Rio Tinto dropping $1.09 to $71.51 and Fortescue Metals lower by 6 cents at $4.53.