* The question of when central bank will finally tighten
* Evans would 'welcome' more ECB easing to boost inflation (New throughout, adds comments to reporters on rates, background, adds byline)
WASHINGTON, April 9 (Reuters) - The Federal Reserve will likely wait at least six months after ending a bond-buying program before raising interest rates, and will only act that quickly "if things really go well," a top U.S. central banker said on Wednesday.
"It could be six, it could be 16 months," Chicago Fed President Charles Evans told reporters on the sidelines of a Levy Economics Institute forum.
Last month, Fed Chair Janet Yellen put the wait at "around six months" depending on the economy. Her comment undercut stocks and bonds and prompted economists to revise forecasts. Traders and Wall Street economists now expect the first rate hike to come around the middle of next year.
"If I had my druthers, I'd want more accommodation and I'd push it into 2016," Evans said of the first rate hike, but "the actual, most likely case I think is probably late 2015."
The Fed has kept rates near zero since the depths of the recession in late 2008, and has bought some $3 trillion in bonds to help lower U.S. borrowing costs. It has reduced its bond-buying and expects to wind it down by the fall.
Evans said the current pace of reducing the bond purchases, $10 billion at each Fed policy meeting, is "reasonable" and takes the Fed "into the October timeframe" for shelving the program.
"I am confident that, depending on how the economic circumstances come out, we'll keep interest rates low for quite some period of time," he said.
WOULD WELCOME ECB EASING
Evans, a vocal policy dove, has long worried that the Fed has been too timid in its efforts to lower employment and raise inflation toward the central bank's targets.
"We're in a very low inflation global environment," he said. "The eurozone well below 1 percent and Japan has been very low for a long period of time, and I'm worried that there's something more afoot" than just the U.S. or eurozone experience.
Asked about a possible further easing of policy by the European Central Bank, he said: "Yes I think that would be quite welcome," adding he would welcome "all actions that help generate stronger world growth."
A fellow dove at the central bank, Minneapolis Fed President Narayana Kocherlakota, has proposed lowering the interest rate the Fed pays banks on excess reserves. The aim would be to provide more accommodation and boost inflation from just above 1 percent currently.
Asked about this idea, Evans said he was willing to look at the possibility, but noted that the Fed's policy-setting Federal Open Market Committee has long considered it and has not acted. (Additional reporting by Ann Saphir; Editing by Andrea Ricci and David Gregorio)