A closely watched survey is indicating that the 19-country eurozone economy started 2015 on a far more solid footing than previously thought.

Financial information company Markit says its purchasing managers' index, a gauge of business activity, rose to a six-month high of 52.6 in January from the previous month's 51.4. January's outcome was better than the initial estimate of 52.2. Anything above 50 indicates expansion.

Among the big-four nations, Markit found output expanded in Germany, Italy and Spain, but the downturn in the French economy extended into its ninth month. Markit also found that the rate of job creation inched up to its best level since mid-2011.

It said developments in Greece and the situation in Russia represent risks to the outlook.