Chinese PMI due at 0145 GMT. A weak reading could spur more selling in the Antipodeans, as China is a key export market for both Australia and New Zealand.
The Aussie fell as low as $0.9662, its weakest since June last year and reversing a climb to $0.9828. It skidded 1.1 percent on Wednesday to last change hands at $0.9688 at 2201 GMT.
A slowing in the Fed's massive monetary stimulus programme could diminish demand for higher-yielding assets, including the Antipodean currencies.
The New Zealand dollar plumbed an 8-1/2-month trough of $0.8057, showing a sharp drop of 1.3 percent, weighed by a broad US dollar rally even as the Fed indicated that the bar to scaling down asset purchases remains high. Kiwi last traded at $0.8058.
The Aussie was 6.5 percent lower so far this month with a test of $0.9581, its 2012 low, in sight.
The Aussie and the kiwi also suffered against other currencies including the euro, which rallied to around A$1.3320 , its weakest since late 2011, and a three-month high around NZ$1.5960.
That pushed the Aussie to 74.9 versus a trade weighted currency basket, a level near an 11-month low hit this week, while the kiwi roughly matched a two-month low hit on Tuesday.
The Aussie and the kiwi have been pounded by the US dollar this month on a resurgent greenback amid signs of improving economic data which has stocked expectations of a tapering in the Fed's easing policy.
Some Fed policymakers have pointed to such a possibility, but minutes from the central bank's latest monetary policy meeting showed board members believe a slow down in asset buying would require further confidence in the economic outlook.
Most technical signs point to more Aussie weakness, but kiwi support holds around $0.8066, the 50 percent retracement of its June-April rally. A break below this level would push the kiwi towards $0.7920, a low hit in September.
Australian government bonds futures are seen tracking a sell-off in US Treasuries, with the three-year contract indicated down 0.070 points at 97.350, while the 10-year contract falls the same amount to 96.665.
New Zealand government bonds slide in early trade, pushing yields 6.5 basis points higher at the long end of the curve.