It will take several years for the ECB to normalize the policy and the closing of net purchases next month is just a first step.
According to Reuters, the Bundesbank and ECB councilor Jens Weidmann said on Tuesday.
"The expected closing of net purchases only marks the beginning of the exit from the ultra-light monetary policy. This is the first step in normalization that will take several years," he said.
At the same time, the ECB should continue to reduce incentives as record low interest rates risk destabilizing the banking system.
"In a downturn, policy-makers need to act vigorously, but in an upturn, when the risks in the financial sector can be built up, they must also be able to tighten the bags once again," he said.