Central bankers need to act quickly and forcefully when rates are low and economic growth is slowing, New York Federal Reserve President John Williams said Thursday.

The influential policymaker delivered a speech discussing what should be done when central banks are near the "zero lower bound," or close to as low as rates can go.

"It's better to take preventative measures than to wait for disaster to unfold," he told the annual meeting of the Central Bank Research Association.

Rather than keep rates elevated to give central banks room to cut in the face of a crisis, Williams said the proper move is not to "keep your powder dry."

"When the ZLB is nowhere in view, one can afford to move slowly and take a 'wait and see' approach to gain additional clarity about potentially adverse economic developments. But not when interest rates are in the vicinity of the ZLB," he said in prepared remarks. "In that case, you want to do the opposite, and vaccinate against further ills. When you only have so much stimulus at your disposal, it pays to act quickly to lower rates at the first sign of economic distress."

Williams spoke as the policymaking Federal Open Market Committee is expected to cut its benchmark interest rate during the July 30-31 meeting. Officials are worried about persistently low inflation, spillover from a global slowdown and the fallout from back-and-forth tariffs between the U.S. and China.

The Fed currently pegs the overnight funds rate in a range between 2.25% and 2.5% — above zero, but still well below normal levels that have prevailed during past economic expansions.

Williams did not directly address whether he favors a cut, though markets are pricing in a 100% chance of a quarter-point reduction and a 38% probability that the Fed might cut by half a point, according to the CME.

However, he said that when faced with low rates and slowing growth, the best strategy is to "take swift action" and "keep interest rates lower for longer."

"The expectation of lower interest rates in the future lowers yields on bonds and thereby fosters more favorable financial conditions overall. This will allow the stimulus to pick up steam, support economic growth over the medium term, and allow inflation to rise," he said.