Speaking at the National Community Reinvestment Coalition annual meeting in Washington, Bernanke said the foreclosure rate was "about four times higher than it was in mid-2005."

"Behind these disturbing statistics are families facing personal and financial hardship," he said.

Bernanke did not signal any Fed intention to cut key bank lending rates, but kept to a review of guidelines proposed in December to keep lenders on the straight and narrow.

"Much of the weakening in underwriting standards appears to have happened outside of institutions regulated by the federal banking agencies," he said.

Bernanke reviewed proposals that included more transparent advertising for mortgages and verification of income and assets before loans are approved.

"The crisis has many roots," he said, stressing, as he has recently, that it would take "a wide array of market participants" to correct the mortgage crisis.