The benchmark S&P/ASX 200 closed 12.8 points lower at 4,200 for the day but added a healthy 98.1 points, or 2.39 percent, over the week.

"The market is up more than two percent for the week so it's hardly surprising at all that we're seeing some profit-taking ahead of such a key event," IG Markets strategist Ben Potter said, referring to Bernanke.

"Given the recent volatility, traders are very reluctant to hold positions over events that have the potential to trigger huge volatility."

The Australian dollar was trading at 104.86 US cents late in the session, up from the 104.56 cents it closed at on Thursday.

Copyright AFP (Agence France-Presse), 2010