The threat came as the Turin-based car giant said it would accept a high court ruling to allow the metalworkers union Fiom to represent workers, Italian media reported.
Fiat's efforts in recent years to introduce more flexible working contracts practices have constantly been blocked by unions, which the company blames for dragging down its loss-making plants. Fiom argues such as move would undermined workers' rights.
While the high-court ruling was a victory for Fiom, Fiat said a new law on worker representation and upholding contracts "cannot be avoided” and that government intervention is an “essential condition” for the company’s continued commitment to Italy.
In July, the Constitutional Court forced Fiat to restore relations with Fiom, the metalworkers’ unit of Italy’s biggest and most left-wing trade union, CGIL. Relations broke down after Fiat refused to sign labour agreements which it felt were unacceptable and said it would no longer deal with Fiom.