Euro zone banks appear reluctant to lend out to the private sector the vast amounts of cheap cash they recently borrowed from the ECB.
The ECB calculated in regular monthly data that growth in loans to the private sector slowed to just 0.7% in February from 1.1% the previous month.
The development is of particular concern given that the ECB lent over €1 trillion to banks at a rock-bottom rate of 1% for a period of three years.
The thinking behind the two unprecedented moves was that banks would lend it on to businesses and households and keep credit flowing in the debt-wracked euro zone economy.
However, since then, daily ECB data show that banks have been parking record amounts of cash in the central bank's overnight storage facility.
In normal times, banks shy away from depositing cash at the ECB, preferring to lend any overnight surplus to other banks where they earn a higher return, but the euro zone debt crisis has spawned a lack of trust between banks.
That means institutions are opting to place the money at the ultra-safe ECB rather than lending it to their peers. The February bank lending data only include the first so-called long-term refinancing operation or LTRO in December where 523 banks queued up to borrow €489.19 billion.
The ECB also calculated that growth of the euro zone money supply, a key indicator of demand in the economy, picked up again in February, with the M3 indicator rising to 2.8% last month from 2.5% in January. The ECB regards the M3 figure as a key guide to inflation pressures and uses it to set interest rates accordingly.
The central bank seeks to keep euro zone inflation below but close to 2% but it stood at 2.7% in February. The central bank cut its benchmark interest rate by a quarter of a percentage point to 1% in December, arguing that future inflation is likely to slow as the euro zone debt crisis puts the brakes on economic growth in the single currency area.
The higher-than-expected M3 growth rate, plus the slowdown in growth in lending to the private sector will mean the ECB is likely to keep its interest rates at current levels for some time to come, analysts said.