WASHINGTON -The Congressional Budget Office (CBO) on Tuesday said the Senate-passed bill to avert the "fiscal cliff" would add roughly 4 trillion dollars to federal deficit over a decade, largely because it would extend low tax rates for most Americans.

In an analysis released on Tuesday, the nonpartisan CBO said compared with the current law, the plan brokered between the White House and the Senate late Monday night would add nearly 4 trillion dollars to the nation's deficit over a decade.

The extension of Bush-era tax rates for most American households under the bill would add about 3.6 trillion dollars to the deficit over the next decade, the CBO said.

The plan would prevent tax rate rise on individuals with annual income below 400,000 dollars and households making up to 450,000 dollars.

The price tag came as the House GOP members wavered on the Senate-passed bill. They expressed concerns over the lack of spending cuts.

House Majority Leader Eric Cantor said he did not support the bill, and a vote in the House has not yet been scheduled.

The reluctance of the House Republicans to endorse the bill made it more likely that the bill would not be accepted as written and may be amended and returned to the Senate, which will bring new uncertainty when the nation has missed the Dec 31 deadline to avoid the "fiscal cliff", a combination of tax hikes and spending cuts which would rekindle a recession.