WASHINGTON — Federal Reserve Chairman Ben Bernanke warned Congress yesterday of a "fiscal crisis" if it doesn't curb the projected growth of federal spending on retirement and healthcare programs.

Echoing similar warnings by his predecessor, Alan Greenspan, Bernanke told the Senate Budget Committee that "the effects on the U.S. economy would be severe" if the government's debt were allowed to balloon as forecast.

Bernanke noted that the federal deficit has declined in the past two years but said that was "the calm before the storm" of skyrocketing expenses for an aging population. He cited Congressional Budget Office projections that spending on the big entitlement programs — Social Security, Medicare and Medicaid — will equal 15 percent of the nation's gross domestic product by 2030, double last year's level.

Bernanke, who was a top White House economic adviser until last year, would not take a position on whether to extend President Bush's tax cuts, many of which are set to expire by 2010. He said he would be nonpartisan as Fed chairman, offering general economic analysis but no specific recommendations on taxes or spending.

The "difficult choices" of how to balance the government's spending and revenue should be made by Congress, the White House and the public, he said.

The federal deficit fell last year to $248 billion, 1.9 percent of the nation's total economic output, by one commonly cited measure. But the deficit would have been $434 billion, or 3.3 percent of gross domestic product, if the government hadn't borrowed from Social Security, Bernanke said.

He also decried "burdensome" tax rules and said Congress might raise tax receipts by making them simpler.