The ECB's governing council is split over whether to cut interest rates again, minutes of their last meeting in Malta have shown, with the issue surfacing as a potential tool to boost inflation.
The European Central Bank has deployed its heavy weapons to lift inflation, including launching a quantitative easing scheme to buy more than €1.1 trillion in sovereign bonds at a rate of €60 billion a month until at least September 2016.
But with inflation at zero in October, central bankers of the 19-member euro zone are mulling over whether to turn to other measures such as further lowering its key lending rate, which is already at a record low of 0.05%.
According to minutes of their meeting on 22 October, some central bankers raised the option of "further lowering policy rates, in particular the rate on the deposit facility".
They noted that jurisdictions that have sent interest rates to negative levels "had not appeared to result in major difficulties or widespread substitution into cash".
The ECB had cut the rate on its deposit facility - that is, for funds placed by banks at the central bank, to negative 0.2% in June 2014.
The rate has remained at that level since. Meanwhile, banks have to actually pay the central bank to keep their cash.
However, there were also critics against a further rate cut, the minutes showed.
Those who were opposed argued that "a rate cut would venture further into uncharted territory and have repercussions on the functioning of markets and the behaviour of banks and customers".
"For this reason, further technical staff and committee work was seen as necessary to assess the benefits and costs, particularly regarding the impact on money markets and on banks' margins and lending capacity," according to the minutes.
ECB chief Mario Draghi had warned last week that signs of a return to healthy inflation levels are fading, in what was seen as a new sign that the bank could ramp up its controversial asset purchase programme.
While falling prices might appear to be good for consumers, they can be poisonous for the economy.
Deflation can become entrenched if consumers delay purchases in the hope of lower prices later, which in turn prompts companies to hold off investment, creating a vicious circle of falling demand and fewer jobs.
The ECB's governing council will next meet early December.