European Central Bank (ECB) chief economist Peter Praet said in Riga on Wednesday that the central bank's quantitative easing was needed as the growth in the Eurozone was below the level it was before the financial crisis, and there were risks to longer-term inflation expectations.

He also said that the central bank should use all instruments available to boost the inflation in the Eurozone.

The value of the ECB's asset-buying programme will be discussed at the monetary policy meeting in December.