Investor morale in the euro zone improved for the third consecutive month in January to its highest level since May, but a turnaround for the 20-country currency bloc is not a done deal, a survey showed on Monday.

Sentix's index for the euro zone rose to -15.8 points in January from -16.8 in December, below a reading of -15.5 estimated in a Reuters poll of analysts.

Sentix pointed to Germany - the region's largest economy - as a pocket of particular weakness, with a decline in sentiment.

"This is unlikely to be a turnaround" for the euro zone, Sentix said. "This is partly due to Germany, whose economy is still in recession and therefore in crisis."

For the euro zone, the expectations index rose to -8.8 points from -9.8 in December, a fourth consecutive month of rises and the highest value since February.

The index on the current situation in the euro zone also rose, increasing to -22.5 in January from -23.5 the previous month, the third monthly increase in a row.

The poll of 1,282 investors was conducted between Jan. 4 and Jan. 6.

(Reporting by Tom Sims, Editing by Linda Pasquini and Miranda Murray)