WASHINGTON (AP) -- The budget deficit for the current year will be $172 billion, according to new estimates by the Congressional Budget Office.

The latest CBO figures, disclosed by a congressional aide, also predict the budget could come back into surplus by 2012, although that would require President Bush's tax cuts to expire at the end of 2010.

But the figures are, at best, a rough estimate. If Bush's tax cuts are extended, along with changes to the alternative minimum tax, the costs would swallow about $300 billion of the projected surplus for 2012, according to prior CBO estimates.

The estimates also understate the ongoing cost of the war in Iraq, but provide a basis for majority Democrats on Capitol Hill to work to match Bush's vow to balance the federal budget in five years.

The improvement in the deficit figure comes as federal tax receipts have continued to grow above estimates. The deficit for the 2006 budget year registered $248 billion.