Fiat has increased its bid to buy Opel and its UK brand Vauxhall from General Motors.
According to Germany's Economy minister Karl-Theodor zu Guttenberg, Fiat has also provided more detail about capital contributions and risk-sharing.
"Interestingly, Fiat has improved its offer once again and we've received a more thorough blueprint from them in the last few hours," said zu Guttenberg. "We're sensing a willingness to negotiate further from all sides."
German government officials are currently discussing at least three rival bids.
Rival bidders to Fiat include Canadian car parts maker Magna and RHJ International, a Brussels-based investment firm.
Fiat has said it will cut fewer than 10,000 jobs if its bid succeeds, but will close one of Opel's four German factories. Magna and RHJ International have pledged not to close any of the German Opel plants.
However, zu Guttenberg has also warned that none of the bids were guaranteed to succeed.
"We must first have a high degree of certainty that the significant tax money we will have to provide is not lost," he said. "From my point of view, none of the three offers so far provides this certainty in a sufficient way."