The European Central Bank (ECB) could still conduct Federal Reserve-style asset purchases and tweak key rates even further, the central bank's vice-president told CNBC on Friday.
Vitor Constancio said that suggestions by ECB President Mario Draghi that the central bank was preparing to buy private sector assets were no "bluff".
"Draghi has hinted clearly in his recent speech that in an extreme scenario … we would need a broader program of asset purchases. It is still on the table," Constancio told CNBC.
Draghi's raft of measures announce Thursday were aimed at combating the threat of growth-sapping deflation in the euro zone and helping the region's economic recovery.
Inflation is currently well below the ECB's target of just under 2 percent, having fallen unexpectedly to 0.5 percent last month, its lowest level since autumn 2009.
In his news conference, Draghi said the central bank was readying for the possible purchase of asset-backed securities (ABS) from banks.
Draghi went on the say that further quantitative-easing measures such as buying sovereign bonds could be considered. Such a program would bring the ECB in line with major central banks like the Fed, Bank of England and the Bank of Japan, all of which have conducted large-scale asset purchasing programs.
However, German Finance Minister Wolfgang Schäuble has been deeply critical of the idea, saying it would amount to covert state funding and would violate European Union law.
Constancio told CNBC that asset purchases could be pursued by the ECB in a "very extreme" situation.
"We all hope we will not even have to consider the possibility," he said.
Constancio also said that the ECB would cut rates still further if necessary. On Thursday, the bank took the unprecedented step of imposing a negative interest rate on banks for their deposits—in effect charging lenders to park money with the central bank. It cut the rate on its deposit facility from 0 percent to minus 0.10 percent—the first time a major central bank has moved rates into negative territory.
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In addition, the central bank cut its main interest rate to 0.15 percent from 0.25 percent, and the rate on its marginal lending facility to 0.40 percent from 0.75 percent.
However, the door is still open for Draghi to alter the rates further, Constancio said. "He (Draghi) said we can still tweak with some of the key rates," the ECB vice-president told CNBC.
Read MoreThe ECB eases and the euro… rises?
Among the other measures announced Thursday, the ECB will launch longer-term refinancing operations (LTROs), in which it lends to banks at low interest rates in order to encourage them to lend to households and non-financial corporations. Plus, it will cease sterilizing the liquidity injected from its Securities Markets Program.