* European car sales rise for fourth month
* Dec gain is biggest monthly rise since Dec 2009
* Year-end sales inflated by more working days
* Renault, VW, Ford, GM, Toyota see double-digit rise (Adds analyst quote, detail, incentive data)
By Andreas Cremer
BERLIN, Jan 16 (Reuters) - Renault, Volkswagen and Ford spurred European car sales to their strongest performance in four years in December, industry data showed on Thursday, as the sector's recovery spread to Mediterranean markets.
Registrations in the European Union and European Free Trade Association trading bloc jumped 13 percent from a year earlier to 948,090 vehicles, the fourth straight monthly gain, the Association of European Carmakers (ACEA) said.
Still, analysts cautioned that two extra working days in the five biggest markets Germany, Britain, France, Italy and Spain, accounting for over three quarters of sales in the region, triggered the massive December boost.
Italy, the region's fourth-biggest market, swung to growth of 1.4 percent, after shrinking for 11 months, as sales in all major markets increased. Greece and Portugal, victims of the euro zone's debt crisis, posted double-digit growth.
"The recovery process in Europe is seemingly taking hold," Matthias Wissmann, head of Germany's VDA auto industry lobby said. "People are building up trust again in the strength of economies."
This year, industry executives and analysts expect a return to low single-digit sales growth in Europe after six years of decline, but caution that chronic excess capacity, which has sparked a price war, will continue to dampen car makers' profitability.
"There were some early signs of green shoots in the final quarter" of 2013, Bernstein analyst Max Warburton said in a Jan. 13 research note. "But it's patchy and far from sufficient to rescue the industry."
The December rally pared the sales decline for 2013 to 1.8 percent or 12.3 million cars, the sixth consecutive year of contraction but a more modest fall than many in the industry had feared earlier in 2013.
London-based Erich Hauser, automotive analyst with International Strategy & Investment was braced for a 7 percent decline last summer.
He ruled out that December statistics were inflated by so-called self-registrations, a controversial practice car makers routinely employ when selling new vehicles to themselves and affiliated dealers, rather than to customers, to overstate demand.
"The recovery may be very slow but a growing number of signs show that the uptrend is intact," Hauser said.
Sales at Renault jumped 29 percent, driven by a 48 percent-surge in sales of its low-cost Dacia brand. Germany's VW, Europe's No. 1 carmaker by volume, posted a 22 percent rise in sales, with double-digit growth extending from luxury flagship Audi to the no-frills Skoda and Seat divisions.
Ford registrations were up 19.5 percent and Toyota, the world's biggest-selling car maker, posted a 10.8 percent increase.
Retail incentives granted across the EU's five largest markets rose by an average 14 percent last year to 2,525 euros ($3,400) per vehicle, according to market research by a major independent pollster.
Even automakers beset with losses or lacking new models won respite across the market of 30 countries.
French carmaker PSA Peugeot Citroen and Italy's Fiat swung back to sales growth of 8.6 percent and 2.3 percent, respectively, from declines of 1.2 percent and 5.8 percent in November.
GM deliveries bounced back to rise 13 percent after falling 3.8 percent a month earlier, even as the U.S. car maker is withdrawing its underperforming Chevrolet marque from Europe to focus on reviving mid-market Opel.
The loss-making Opel/Vauxhall brands sprung back to 22 percent growth, after a 3.1 percent drop in November. ($1 = 0.7356 euros) (Editing by John Stonestreet and Susan Fenton)