UPDATE 1-Brazil '09 auto sales post record year-source

* Brazil new auto sales in 2009 post record

* December sales up about 16.5 pct over November

* December sales jump 51.1 pct over year-ago period

SAO PAUL, Jan 4 (Reuters) - New auto sales in Brazil posted a third straight record year in 2009, a source with knowledge of the official data told Reuters on Monday, underscoring the importance of domestic demand in Latin America's largest economy.

About 3.01 million units were sold in Brazil in 2009, the source said, an increase of about 51.1 percent over the year earlier period.

Sales of new cars, light vehicles, trucks and buses in December tallied 277,966 units, the source said, for a jump of about 16.5 percent over November.

Last year's gains came as the government slashed taxes for a number of goods, including cars, to stoke consumer demand as the global financial crisis took its toll.

Brazilians, in turn, flocked to showrooms, boosting sales and helping pull the country out of recession in the second quarter.

Brazil's national dealers' association, Fenabrave, is slated to release the official data on Tuesday.

Brazil is a major market for global automakers such as Italy's Fiat SpA (FIA.MI), Germany's Volkswagen AG (VOWG.DE), and U.S.-based General Motors Co [GM.UL] and Ford Motor Co (F.N). (Reporting by Alberto Alerigi Jr.; Writing by Luciana Lopez. Editing by Robert MacMillan)