Investor nervousness weighed on the market as the deadline approaches to resolve the US political deadlock over the debt ceiling.
At the close on Monday, the benchmark S&P/ASX 200 Index was down 23 points, or 0.44 per cent, at 5207.9, while the broader All Ordinaries was down 22.3 points, or 0.43 per cent, at 5206.5.
US politicians have until Friday (Australian time) to reach a deal to prevent a huge default on the country's debt obligations.
CommSec analyst Steve Daghlian said the market lost ground on Monday over worries in the US. It also followed the weekend release of disappointing Chinese export figures.
"The US government shutdown is still a concern and that's keeping investors on edge and keeping the Aussie dollar strong at this point," Mr Daghlian said. "Most sectors are in the red."
Mining and energy stocks lost ground, with global miner BHP Billiton 11¢ lower at $35.02, and Rio Tinto 6¢ weaker at $61.65.
OZ Minerals fell 6.6 per cent to $4.11 after it failed to meet production levels at its Prominent Hill mine in South Australia.
Santos closed 1.8 per cent lower at $14.53 while Origin Energy was 0.42 per cent lower at $14.17.
Among the banks, ANZ fell 15¢ to $31.14, NAB dipped 11¢ to $34.76 and Westpac fell 4¢ to $32.95. Commonwealth Bank bucked the trend, closing 20¢ higher at $72.52.
Insurance comparison business iSelect was 10¢ higher at $1.36 after its CEO resigned just a few months after taking the company public.
Gold was $US1273.50 an ounce, down $US18.53. The dollar was at US94.67¢, up slightly on the day.
The local bond market was slightly firmer as investors waited for a resolution in the US.
UBS interest rate strategist Matthew Johnson said investors did not seem to be rapidly moving into safe assets. "I doubt that things will turn bad immediately," he said.
The December 10-year bond futures contract was trading at 95.920, up from 95.910 on Friday. The three-year contract was at 96.900, up from 96.860.
On Tuesday, the Reserve Bank will release the minutes of its October meeting, which may show it is more positive about the economic outlook.