The White House on Tuesday said President Barack Obama would veto Keystone XL pipeline legislation if it passes under the new Republican-led U.S. Congress.

A bill that would have forced Obama's hand on the issue failed to clear Congress in its final days last year. But the Congress that convened Tuesday and new Senate Majority Leader Mitch McConnell has said the pipeline bill will be among the first issues voted on.

White House spokesman Josh Earnest said a "well-established" review by the State Department should not be undermined by legislation.

Read MoreNew GOP Congress, new Keystone pipeline bill



The administration also said the pipeline's route through Nebraska must be resolved.



Earlier this week, the administration said Obama believed the proposed pipeline would have little impact on U.S. gas prices.

The two main sponsors, Sen. Joe Manchin, D-W.Va., and Sen. John Hoeven, R-N.D., said Tuesday morning they had enough votes to overcome a filibuster of the bill but not a presidential veto. The House is expected to vote and pass a bill approving the $5.4 billion project, which was first proposed in 2008, on Friday.

The head of the American Petroleum Institute, Jack Gerrard, said Tuesday after his annual speech on the state of U.S. energy that the president had failed to make a simple decision that would put people to work, but he predicted the pipeline would eventually be approved.