FRANKFURT (Reuters) - The European Central Bank's monetary policy is proving to be "very effective" and the bank will review its policy stance in December, ECB President Mario Draghi said in a letter to a Member of European Parliament.

"We have ample evidence that our measures have substantially eased the borrowing conditions of firms and households, strengthened credit creation and, hence, supported the momentum of the euro area’s economic recovery," Draghi said.

"The Governing Council remains committed to preserving the very substantial degree of monetary accommodation which is necessary to secure a sustained convergence of inflation toward levels below, but close to, 2 percent over the medium term."

(Reporting by Balazs Koranyi; Editing by Francesco Canepa)