"The risk that we do not fulfill our mandate of price stability is higher than six months ago," Draghi was quoted as saying in an interview that will be published on Friday.
"We are in technical preparations to adjust the size, speed and compositions of our measures early 2015, should it become necessary to react to a too long period of low inflation. There is unanimity within the Governing Council on this."
He added that government bond purchases were among the tools the ECB could use to fulfill its mandate, but that state financing -- which is prohibited by the EU treaty -- had to be avoided.
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Printing money to buy government bonds, a step known as quantitative easing (QE), is seen as one of the last tools the ECB has to revive inflation, with the key interest rate at 0.05 percent and growing doubts about the impact of earlier measures.
Euro zone inflation stands at 0.3 percent, far below the ECB's target of just under 2 percent, and calls for more ECB action have grown louder as policymakers warn that plunging oil prices could push inflation below zero in coming months.
Concerns are that weaker price expectations could affect wages and investments and dampen growth prospects.
Regardless, Draghi ruled out a break-up of the euro zone.
"A break-up of the euro zone? That will not happen. That's why there is no plan B," he said.
Draghi also said he had no desire to enter politics.
"I do not want to be a politician," Draghi said.
On Wednesday, Italy's 89-year-old President Giorgio Napolitano said he would because of his age. Commentators have mentioned Draghi as a possible successor in recent months.
Asked by Handelsblatt whether he would be interested in succeeding Napolitano, Draghi said: "My mandate as ECB president continues until the year 2019."