WASHINGTON – The Obama administration will raise its forecast for the 10-year federal budget deficit to about $9 trillion from $7.1 trillion, a senior administration official said.

The White House will try to use the new estimate as extra ammunition as it seeks a health-care overhaul in Congress. The administration says its policies are aimed at driving down long-term medical costs. The estimate reflects the grim long-term U.S. fiscal outlook, as baby boomers retire in increasing numbers and costs continue to soar for federal entitlements, particularly health-care programs such as Medicare.

The latest measurement puts the White House in line with previous updates from the Congressional Budget Office. The change stems in part from downward revisions of projected economic activity since late 2008, when the administration began putting together its latest forecast.

Earlier this week, the administration said it would shrink its estimate for the 2009 deficit to about $1.58 trillion from $1.84 trillion. That is because of generally lower-than-anticipated costs for various financial-sector bailouts. But CBO's estimate could vary significantly, some budget experts say.

By any measure, the 2009 budget deficit is expected to be the widest since World War II as a percentage of the economy.