WASHINGTON - The full U.S. Senate seems certain to put off until next month a vote to reconfirm Ben Bernanke to a second term as chairman of the Federal Reserve, a Democratic aide said on Wednesday.

The aide said that with Senate Democrats trying to reach an agreement on healthcare before wrapping up business for the year, they appear on track to put off a vote on Bernanke's nomination until lawmakers return from a holiday break in January.

There simply doesn't appear to be any time to do it this year, the aide said.

The Senate Banking Committee is expected to vote to back Bernanke's nomination to a second four-year term at the helm of the Fed -- the U.S. central bank -- on Thursday, despite opposition from some Republicans. The action would send the nomination to the full Senate for a final vote.

His first term expires on January 31 although he could continue to serve as acting chairman after that.

(Reporting by Thomas Ferraro; Editing by James Dalgleish)