Sen. Bernie Sanders (I-Vt.) said Monday he's "cautiously optimistic" his modified amendment to audit the Federal Reserve would pass the Senate this week.

Sanders said he expected a vote on his amendment to Democrats' Wall Street reform bill sometime this week, possibly as early as Tuesday.

"I hope we have the votes, and I'm cautiously optimistic that we will," Sanders said this morning during an appearance on the liberal Bill Press radio show.

Sanders has been pushing an amendment meant to mirror one offered by Rep. Ron Paul (R-Texas) in the House that would open the Fed's books, particularly when it comes to its actions over the past years to assist some of the nation's top financial institutions.

The Obama administration and many top Democrats in Congress had opposed the proposal until Sanders agreed last week to modify the amendment to ensure the audit won't touch upon the Fed's open market practices to set monetary policy.

"It had never been my intention to get the United States Congress involved in monetary policy, interest rates, etc.," Sanders said Monday.

The modified amendment subsequently won support from Sen. Chris Dodd (D-Conn.), the Banking Committee chairman who authored the Wall Street reform bill, and from a top Treasury Department official.

The vote on the Amendment, the independent senator said, could be as soon as tomorrow.

"They're probably going to work that out today," he explained. "I don't know for sure, but I hope tomorrow."