"Investor confidence in the view that the US Federal Reserve would announce the beginning of a wind-down in its quantitative easing asset purchase program in mid-September has been shaken in recent days," Macquarie Research said this morning.

"Concerns about a military strike against the Syrian government and the US debt ceiling debate have increased unease about the impact of the US Fed's proposed QE tapering strategy on the strength and stability of the global economy.

"Taken together, the developments have undermined the strong conviction of most Fed watchers (including ourselves) that the US Federal Reserve would commence winding back its $US85 billion per month bond-buying program at its 17-18 September Federal Open Market Committee meeting."

Commodity prices were impacted by strength in the US dollar this week. One gauge is the Australian dollar, which sank 1% against the greenback this week to US89.36c.

London Metal Exchange cash copper is still in high territory as it closed at $7129.75 a tonne overnight - a fall of 2.8% since last Friday.

By the same comparison LME spot nickel was down 3.1% to $14,001/t.

Singapore Tapis crude closed at $121.76 a barrel overnight, a jump of 4.85% since last Friday due to Syria-related fears.

Spot gold prices were trading around $1409.71 an ounce in the past 30 minutes. It is a little less than a 1% gain since last Friday.

Despite the spike in oil prices, Oil Search and Santos only posted modest gains this week, while ExxonMobil shares lost ground.