UPDATE 1-Italy industry output unexpectedly rises in August

(Adds economist quotes)

* Italian output jumps 1.7 pct m/m in August * Beats analyst forecasts for a decline * ISTAT cautions on seasonal distortions By Catherine Hornby

ROME, Oct 10 (Reuters) - Italian industrial output unexpectedly rose in August, offering some hope that recession may be easing slightly although the statistics bureau cautioned that seasonal factors may have distorted the data.

Output rose 1.7 percent month-on-month after an upwardly revised 0.1 percent fall in July. The figure beat all forecasts in a Reuters poll that had spanned -1.4 percent and +1.6 percent and averaged -0.4 percent.

August output data in Italy can be highly erratic because many factories are closed for the summer break, making seasonal adjustment more important and more difficult than in other months, a spokesman for the national statistics office ISTAT said.

"It nevertheless shows some positive trends in industry, but we will have to wait for September and October data to see if those trends continue," the spokesman said.

The euro zone's third-biggest economy has been mired in recession since the middle of last year. It shrank 0.8 percent in the second quarter of 2012 compared to the first, and shrank 2.6 percent compared to the same period a year earlier.

Unicredit analyst Chiara Corsa said the output data was "undoubtedly strong" even when considering seasonal factors. She said it confirmed her expectation that the pace of recession would ease in the third quarter to about -0.6 percent.

Paolo Mameli from Intesa Sanpaolo said he may revise up his forecast for the economy to contract by 0.7 percent in the third quarter following the data, though he expected the rise in output in August would be reversed in September.

Italy's economic slump has been accentuated by austerity measures adopted by Mario Monti's technocrat government when he took office at the end of last year, aimed at heading off a debt crisis.

The government said in September it expected the economy would shrink this year by 2.4 percent, twice as much as the previous projection of a 1.2 percent drop, made in April.

ISTAT has said it expects the economy may contract slightly less than the government forecasts this year, pointing to signs of an improvement in industrial output and confidence in the second half of the year.

In August, output rose in the consumer and investment goods sector and in the energy industry, while falling slightly in the intermediate goods sector, Wednesday's data showed.

The overall rise in Italy's output mirrored a better than expected 1.5 percent surge in French industrial output in August, while output in Germany, Europe's largest economy, fell 0.5 percent due to a weaker construction sector.

Germany, France and Italy make up around two thirds of total euro zone industrial output. Aggregate data for the currency bloc will be released on Friday.

On a work-day adjusted year-on-year basis, Italian output in August was down 5.2 percent, compared to a 7.2 percent decline in July.

(Additional reporting by Elvira Pollina, Andrea Mandala and Giulio Piovaccari; Editing by Susan Fenton)

((catherine.hornby@thomsonreuters.com)(+ 39 0685 224 394)(Reuters Messaging: catherine.hornby.thomsonreuters.com@reuters.net))