WASHINGTON — President Obama will ask Congress this week for $1.2 trillion in additional borrowing authority, which would raise the federal debt limit to $16.4 trillion and avoid the need for further increases before the 2012 elections, administration officials said Tuesday.

This would be the final increase allowed under the budget agreement reached in August after the government came close to default. Since signing legislation to codify that agreement on Aug. 2, Mr. Obama has obtained two increases totaling $900 billion.

The budget agreement largely pre-empts the partisan debate over federal deficits and debt that the request might otherwise have touched off in Congress.

While the House, controlled by Republicans, could try to block the proposed increase in the debt limit, the Senate, with a Democratic majority, is unlikely to go along. If both houses of Congress voted to block the increase, Mr. Obama could veto the legislation.