* Exports to make small contribution to Q3 growth
* Exports should grow given strong industrial orders
* Consumption remains main growth driver (Adds retail sales)
BERLIN, Nov 9 (Reuters) - Germany's imports and exports both fell in September as its trade surplus widened, highlighting the importance of domestic consumption as a driver of growth in Europe's largest economy.
Seasonally adjusted exports fell by 0.4 percent on the month while imports were down by 1.0 percent, Federal Statistics Office data showed on Thursday.
The reading, which followed months of growth in both exports and imports, showed sales of German goods and services abroad barely grew overall in the third quarter.
Economists said trade would not make any significant contribution to growth in the quarter, but they were optimistic about the outlook given continuing strong demand for German goods.
Industrial companies registered a 3.6 percent increase in orders in August after contracts for "Made in Germany" goods fell by an upwardly revised 0.4 percent in July, data this week showed. Demand has come from both its euro zone partners and from customers outside the region.
"Even the strong euro has not clouded the outlook for exports," said Ulrike Kastens of Sal. Oppenheim.
Export growth has been slowing, however, leaving the economy relying more on consumption, state spending and construction as drivers.
Retail sales would rise 3 percent this year, the sector's HDE association said on Thursday, exceeding the half-a-trillion-euro mark for the first time.
Over the Christmas period, sales would also rise 3 percent, it said - less than in the last two years.
A Reuters poll had forecast exports would fall by 1.1 percent and imports rise by 0.3 percent.
The seasonally adjusted trade surplus widened to 21.8 billion euros from a downwardly revised 21.3 billion euros ($24.73 billion) in August.
Germany's wider current account surplus, which measures the flow of goods, services and investments, rose to 25.4 billion euros after an upwardly revised reading of 18.0 billion euros in August, unadjusted data showed.
Both exports and imports figures for August were revised down. Exports grew by 2 percent from a previous reading of 3.1 percent. Imports rose by 0.8 percent instead of a previously reported increase of 1.2 percent.
($1 = 0.8613 euros) (Additional reporting by Rene Wagner; Editing by Paul Carrel and John Stonestreet)