Both the Sueddeutsche Zeitung newspaper and Focus magazine reported, citing unidentified sources, that Fiat CEO Sergio Marchionne expects to meet Monday with German Economy Minister Karl-Theodor zu Guttenberg and Foreign minister Frank-Walter Steinmeier to present a concept for taking over Opel.
There was no immediate confirmation from the German government.
GM has been trying to find investors for its non-core and nonprofitable assets as part of a restructuring in which it has sought billions of dollars in aid from the U.S. government to avert its collapse.
Opel has said it needs euro3.3 billion ($4.3 billion) to get through the economic crisis, while the German government has said it doesn't foresee giving direct state aid. Chancellor Angela Merkel has suggested the government could help an Opel investor with loan guarantees.
Several suitors have been reportedly interested, with Fiat and Canadian car parts maker Magna International Inc. two leading the way.
Magna already on Tuesday presented Guttenberg with what the minister called a "rough concept for a commitment with Opel."