AUD/USD eased 0.18% to 0.7606.
Market sentiment was hit after three explosions in Brussels killed 34 people and injured hundreds on Tuesday.
Global terrorist organization ISIS claimed responsibility for the attacks that took place in the city's airport and a metro station.
NZD/USD slid 0.39% to trade ar 0.6726.
Meanwhile, the greenback found support after Philadelphia Fed President Patrick Harker said late Tuesday that the U.S. central bank should raise interest rates as early as next month if the U.S. economy continues to improve.
The comments came a day after Atlanta Federal Reserve President Dennis Lockhart signaled that the Fed could hike interest rates in April.
Market participants were eyeing the release of U.S. new home sales data due later in the day, as well as a report on New Zealand's trade balance.
The U.S. dollar index, which measures the greenback's strength against a trade-weighted basket of six major currencies, was up 0.18% at 95.84, the highest since March 17.