The euro zone's unemployment rate remained stuck at 12 percent for December, although the number of jobless people in the region fell by 129,000 - the largest monthly fall since the start of the financial crisis.
Breaking the PMI data down to a country level, Ireland, Germany and Spain were among those that reported strengthening economies, with Germany's output growth coming in at 55.5 - a 31-month high - and Spain's rising to a 78-month high of 54.8.
(Read more: Deflation fears back: Euro zone inflation falls again)
France, however, continued to lag behind its European counterparts. Its composite PMI came in a 48.9 in January following contractions in both the manufacturing and services sectors, although this was a 3-month high for the country.
Howard Archer, chief European economist at IHS Global Insight, said the data was "modestly supportive" of growth hopes for the region, with most euro zone countries seeing improved performances.
"Particularly welcome news saw Spanish services expansion pick up to a 78-month high which boosts hopes that the economy can establish sustainable recovery over the coming months," he said.
"French services activity contracted for a third month running in January, albeit at a reduced rate... This does little to dilute reinforces concern over the underlying state of the French economy."