Fiat SpA's (F.MI) main unions said Friday they are pressing the Italian government and the company's management for an urgent meeting, fearing job losses from a potential merger between the carmaker and General Motors Corp.'s (GM) unit Adam Opel AG.

The unions - Fiom, Fim, Uilm and Fismic - will also hold a rally in Turin Saturday to raise the issues of potential job losses and the crisis in the automobile sector.

"We haven't had any meeting with Fiat's management since the crisis started," Fiom told Dow Jones Newswires.

"Apparently, the management wants to strike a deal with GM before starting negotiations with the unions," Fiom said.

The German government has set May 20 as the deadline to submit offers for Adam Opel.

-By Luca Casiraghi, Dow Jones Newswires; +39 02 5821 9907; luca.casiraghi@dowjones.com