"Accommodative policies will likely be warranted for an extended period," said Bernanke speaking at a Fed conference on Thursday.
Bernanke also noted that policymakers were thinking how to terminate support as recovery sets in.
"At some point, however, as economic recovery takes hold, we will need to tighten monetary policy to prevent the emergence of an inflation problem down the road," he was quoted as saying by Reuters.
The US central bank has cut interest rates to near zero percent and pumped hundreds of billions of dollars into the financial system to counter the current financial crisis.
Bernanke sent a signal that the Fed is gradually but steadily moving toward an exit from its supportive policies, even while evidence of the recovery has been mixed.
Last week, a report showed that US employers shed more jobs than expected in September dented confidence in the recovery.
However, data released on Thursday showed gains in retail sales and reinvigorated optimism.
Fed continues to prop up US economy