The U.S. central bank has kept rates near zero since December 2008, and the Fed had since December 2012 promised to keep them there until the unemployment rate fell to at least 6.5 percent, as long as inflation did not threaten to rise above 2.5 percent.
With unemployment now at 6.7 percent, and the Fed's preferred gauge of inflation little more than half of its 2-percent target, policymakers decided to jettison what many said were becoming increasingly irrelevant guidelines.
But to Kocherlakota, one of the Fed's most dovish policymakers, dropping any reference to those thresholds "does not communicate purposeful steps being taken to facilitate a more rapid increase of inflation back to the 2 percent target," Kocherlakota said, and suggests "the committee views persistently sub-2-percent inflation as an acceptable outcome."
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It also creates uncertainty over economic growth prospects, he said, by giving little information about how fast the Fed wants the economy to return to full employment, and even about the level of unemployment it views as being consistent with full employment.
Kocherlakota has been pressing for the Fed to promise low rates until unemployment reaches the more normal level of 5.5 percent even before the Fed adopted the 6.5 percent unemployment threshold for considering any rate rise.
The promise, he said, should be contingent on inflation rising no more than a quarter of a percentage point above the Fed's 2-percent target, a stipulation he repeated on Friday.
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New in his proposal was a caveat that low rates would also be contingent on possible risks to financial stability remaining contained, a nod to the concern that some Fed officials have over the potential for sustained near-zero rates to foster unseen bubbles.
Kocherlakota said he agreed with one aspect of the Fed's new policy: its stated intent to keep rates below normal levels for some time even after inflation and the labor market return to more normal levels.