CHARLOTTE, N.C., April 17 (Reuters) - The Federal Reserve's highly decentralized system is an asset that should not be tampered with as policy-makers review modernizing the country's financial regulations, a top Fed official said on Thursday.

"I think there are important questions on the table about the structure of regulatory authority and responsibility at the national (level)," Richmond Federal Reserve President Jeffrey Lacker told reporters on the sidelines of a conference here.

"But no matter how that comes out, I think the structure of the Federal Reserve system has served this country very well and in my view it ought to be preserved," he said.

A plan by the U.S. Treasury to shake up the country's financial regulators in the aftermath of the collapse of the subprime mortgage market has questioned whether the 12 regional Fed branches should continue to supervise state-chartered banks.

It recommended a study "that examines the evolving nature of the Federal Reserve Banks," which has alarmed Fed insiders, who fear they are in the firing line as U.S. lawmakers debate the housing crisis during a partisan election year.

The Fed's current structure of a centralized Board of Governors in Washington and 12 regional branches -- whose presidents vote, on an annually rotating basis on interest rate decisions -- was established by Congress in 1913.

The Fed currently supervises bank holding companies and state-chartered banks that opt to be members of its system.

The other bank supervisors are the Office of the Comptroller of the Currency, the Federal Deposit Insurance Corp and the Office of Thrift Supervision.

Treasury's blueprint would streamline the number of supervisors and charge the Fed with ensuring market stability.