"It pushes people not to spend. This is one of the factors affecting consumer confidence and consumer spending," John Williams, president of the San Francisco Federal Reserve Bank, said in a question-and-answer session after a speech in Honolulu.

"Given where oil prices have gone, it's part of the story for (expectations of) modest growth."

However, a severe supply shock in the Middle East would have a more negative impact if it sent prices sharply higher, he said.

Williams, a voting member this year on the Fed's policy-setting panel, has supported recent moves by the U.S. central bank to bolster what he has termed as a "lackluster" economic recovery.

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(Writing by Kim Coghill; Editing by Ramya Venugopal)

• A Permanent Economic Emergency