* Output rises in June for 2nd month, up 8.4 pct from May

* Anfavea boosts estimate for 2009 sales to 6.4 pct rise

* Sales surge 21.5 pct to a record 300,002 units

* Fiat remains market leader in June, sales up 16.5 pct (Recasts; Adds new forecasts in third, fourth paragraphs)

Automobile output in Brazil climbed in June for the second straight month as manufacturers stepped up production to meet growing consumer demand, the national automakers' association Anfavea said on Monday.

Production rose 8.4 percent to 283,900 units in June from the previous month, Anfavea said in a press release distributed in Sao Paulo. On a year-on-year basis, however, output slumped 8.2 percent last month.

Sales also surged 21.5 percent in June to a record 300,002 units from the previous month, and 17.2 percent from June 2008, the group said. Sales might be headed for a third record year, the group said on Monday.

Anfavea also raised its forecast to an increase in car sales this year of 6.4 percent from a 3.9 percent decline previously. Output will probably fall 5.2 percent this year, it said, less than the 11 percent drop estimated previously by the group.

A combination of tax breaks, lower prices and improved confidence has sent consumers flocking to showrooms, industry executives said last week. The June data underscore the success of President Luiz Inacio Lula da Silva's tax breaks on vehicles and home appliances to revive industrial production and pull the $2 trillion economy out of recession.

There has been an improvement overall in terms and conditions of credit and confidence, turning in another healthy month for the sector, said Alexandre Andrade, an auto industry analyst at Sao Paulo-based consulting firm Tendencias.

Last week, Lula renewed tax breaks for purchases of vehicles until December. The renewal of the tax breaks might allow auto retailers to lower prices even more, government officials said last week.

Brazil, Latin America's largest economy, 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 Corp (GMGMQ.PK) and Ford Motor Co (F.N). Asian and French manufacturers are also increasingly relying on Brazil to offset slumping sales at home.

Fiat remained the market leader in June, selling 70,645 cars and small trucks, a 16.5 percent increase over May. Volkswagen sold 66,849 units last month, up 20 percent from May.

GM's sales surged 22.5 percent last month, totaling 58,634 units. Ford, the fourth-ranked automaker in Brazil, saw sales jump 32 percent to 58,634 units.

Brazil's national dealers' association, known as Fenabrave, had already said last week that sales had jumped to a record high in June, helped by growing consumer confidence and government tax breaks.

But sales of trucks are lagging behind those of family vehicles, indicating that investments are being pared in the wake of the global financial crisis, Tendencias' Andrade said. (Reporting by Alberto Alerigi Jr., Writing by Guillermo Parra-Bernal, Editing by Maureen Bavdek and Gerald E. McCormick)