One of the members of the European Central Bank's (ECB) executive board, Sabine Lautenschlaeger, expressed doubt Thursday that the ECB's controversial bond purchase program will have the desired effect. "Given the current low level of interest rates in the eurozone, I have doubts whether the economic effects of the purchase program will reach the desired magnitude," Lautenschlaeger told the weekly magazine WirtschaftsWoche in an interview.

The ECB launched a program of so-called quantitative easing (QE) - or the wide-scale purchase of sovereign bonds - at the beginning of March in order to drive inflation higher in the 19 countries that share the euro and help kick-start economic recovery.

Under the program, the ECB aims to buy 1.14 trillion euros ($1.2 trillion) worth of bonds between now and September 2016 at a rate of 60 billion euros per month. "Experience in the United States shows that sovereign bond purchases are more effective the higher yields are," Lautenschlaeger said.

She warned that low interest rates could lead to the formation of asset price bubbles. "When interest rates are low, the danger increases of risky investment behavior, and that can easily lead to overheating or to price bubbles in other asset classes," she argued.

In addition, low interest rates took the pressure off governments to push through economic reforms and get their finances in order. Before joining the ECB's executive board, which is responsible for the day-to-day running of the bank, Lautenschlaeger was vice president of Bundesbank, the German central bank. Her skepticism towards the QE program is shared by Bundesbank chief Jens Weidmann. As of March 27, the ECB had acquired 41.02 billion euros of sovereign bonds under the program, according to data published on the ECB website.