WASHINGTON (Reuters) - Republican Senator Rand Paul plans to put a "hold" on the nomination of Janet Yellen to be chair of the Federal Reserve, CNBC reported, a move that would force supporters to round up 60 votes in the 100 seat Senate to confirm her.

CNBC, citing a source close to the Kentucky lawmaker, said Mr Paul was insisting on a vote on a bill he has sponsored to open up the United States central bank's monetary policy decisions to congressional audit.

Mr Paul's office did not immediately respond to a request for comment.

The White House was always expected to have to secure 60 votes for the nomination to clear procedural roadblocks, and Democrats have repeatedly expressed confidence in their ability to do so. Democrats control the Senate 55-45 and would need only five Republicans to support Yellen.

The Senate Banking Committee, which needs to vet the nomination before it goes before the full Senate, is not likely to hold a hearing on the matter until mid-November. Democrats have an edge of four votes on the panel.

Although Ms Yellen, currently the Fed's vice chair, is expected to win Senate confirmation, the process is likely to be contentious. Many Republicans have criticized the central bank's aggressive easing of monetary policy as a dangerous courtship of inflation that also risks fuelling asset bubbles.

To lay groundwork ahead of her hearing, Ms Yellen has been lining up meetings with key members of the banking committee.

She plans to meet with Republican Senator Richard Shelby next week and Senator Bob Corker, also a Republican, is in talks to set up a meeting.

Both have been expected to oppose her nomination.