* Q1 operating profit 2.9 bln euros vs 2.3 bln a year ago
* VW repeats profit, sales and revenue outlook
* Analsyst say full-year guidance may be too conservative
(Adds analyst comment, detail and share price)
BERLIN, April 29 (Reuters) - Record sales of luxury Audis and Porsches boosted Volkswagen's operating profit 22 percent in the first quarter, and analysts said they expected the German carmaker to revise its full-year earnings guidance upwards.
Publishing first-quarter results on Tuesday, VW stuck to its outlook given in February, saying group operating margin could be between 5.5 and 6.5 percent after 5.9 percent last year. In February it also said a new full-year profit record would require economic conditions to improve, especially in Europe.
But analysts said the carmaker was understating its prospects. Its first-quarter operating profit of 2.86 billion euros ($3.96 billion) beat the average estimate in a Reuters poll of analysts by over four percent.
"There's an 80-percent chance that VW will raise its guidance in the next 3-4 months," Frankfurt-based Metzler Bank analyst Juergen Pieper said, citing the European recovery and growing savings from modular production.
European car sales, which make up 40 percent of VW group sales, posted a seventh straight monthly gain in March following a six-year slump that cut registrations to a 20-year low. VW is running extra production shifts at its main Wolfsburg plant during the second quarter on excess demand for the Golf and Tiguan models.
Quarterly deliveries of Audis and Porsches, which account for about two-thirds of VW group EBIT, rose 11.7 percent and 4.5 percent respectively to 413,000 and 38,700 cars.
VW shares were trading 0.18 percent higher at 192.00 euros as of 1241 GMT.
VW's results in the first quarter of 2013 had been hit by about 350 million euros of provisions at the engineering division MAN SE for a failed power plant project, and the cost of an overseas vehicle recall.
VW expects to increase group deliveries slightly from last year's record 9.7 million vehicles, and says will come in within a range of 3 percent around last year's 197 billion euros. ($1 = 0.7223 Euros)
(Reporting by Andreas Cremer; Editing by David Goodman)