Revealing his intentions in an interview with the Financial Times, Marchionne said he wanted to build a European car giant with Fiat, Chrysler and Opel by forming a new publicly traded company with revenues of about €80 billion ($106 billion) and sales of six or seven million vehicles a year.
Marchionne will meet German Economy Minister Karl-Theodor zu Guttenberg and Foreign Minister Frank-Walter Steinmeier in Berlin on Monday, where he is expected to discuss the idea.
"From an engineering and industrial point of view, this is a marriage made in heaven," he told the FT, adding that a union of Opel and Fiat would save €1 billion a year.
The FT suggested that, based on past mergers and the two companies' existing size, the merger could result in the loss of up to 9,000 jobs.
And Guttenberg told German broadcaster Deutschlandfunk that Berlin was not prepared to back an Italian rescue of Opel unless it had a solid foundation. Any deal had "to make sense," he said, adding that the government wanted to hear "more concrete" details as to how Fiat would fund a takeover of Opel.