Markit's composite purchasing manager's index (PMI) released Wednesday, for instance, rose to 52.9 in January, up from 52.1 in December. It was, however, lower than the flash estimate of 53.2 (a reading over 50 marks expansion).
The uptick was driven by the manufacturing industry, where accelerating new orders and export business pushed the rate of expansion close to a three-year high.
(Read more: Euro zone business activity rises beyond expectations)
Meanwhile, jobless data released Friday showed that although the unemployment rate remained stuck at 12 percent in the euro zone, the number of people out of work fell by 129,000 in December.
As such, Brzeski said the balance was tipped towards no action this week, but added: "Since November last year, we know to take the ECB's determination to fight any deflationary threats seriously. It would be a mistake to underestimate the ECB's willingness for pre-emptive strikes."
Despite some uncertainty about timing, however, economists are agreed that deflationary concerns have increased the pressure on the ECB and put its inflation forecasts in the spotlight.
Daiwa Capital Markets' Chris Scicluna and Emily Nicol argued that the ECB was likely to "temporarily refrain" from significantly revising their assessment of deflationary risks. This is because although the headline inflation rate declined in January, the drop was caused by lower energy prices and core inflation moved upwards as expected.
But they added: "While we think that the Governing Council is, on balance, just about more likely than not to leave policy unchanged next week, we also now think that it will have to follow through on its forward guidance and cut rates again in March."
Societe Generale's Legland agreed. "For now, the ECB remains in a wait-and-see mode. It is however likely that it will be forced to act – and this is only a question of time."