Italy's CGIL trade union, the biggest labor group in Fiat, on May 4 said the Italian auto giant must promise that production would be maintained in Italy even if it bought Germany's Opel.
Any Opel deal "will inevitably lead to restructuring. We are therefore asking for guarantees that the Italian plants are not closed," Vittorio De Martino, representative of Fiom-CGIL at Fiat's Mirafiori plant, said.
De Martino said he was worried because "there is an overlap of ranges" between Fiat and Opel, adding that this not a problem with Chrysler, which Fiat announced a new partnership with last week.
Fiat has already implemented thousands of temporary layoffs at its Italian factories this year to lower production and costs amid a collapse in demand in the global financial crisis that has hit automakers worldwide.
Fiat boss Sergio Marchionne has said he cannot rule out factory closures.
Fiat Group employs more than 82,000 people in Italy including 30,000 in its auto division, making it by far the country's biggest private sector employer. It has five auto assembly plants spread around Italy.
Copyright Agence France-Presse, 2009