The holding company RHJ International was due to hold talks on Wednesday at the German economy ministry about its rival bid for Opel, sources told news agency AFP.

Berlin agreed in late May to support a Magna bid for a majority stake in Opel in conjunction with state-owned Russian bank Sberbank and GAZ, with cheap loans and loan guarantees.

But the deal is far from done and dusted, with GM, which emerged from bankruptcy on Friday, also receiving interest from Brussels-based RHJ and from China’s Beijing Automotive Industry Company (BAIC).

RHJ is expected to offer about US$300m (EUR215m) for majority control of Opel, which employs 55,000 people in Europe, Dow Jones Newswires cited a person familiar with the situation as saying on Tuesday.

The offer could come as soon as today (Wednesday), with GM also likely to receive a tweaked bid from Magna, which appears to be readying for a deal this weekend, this person said.

Roland Koch, the premier of the German state of Hesse where Opel has one of its biggest plants, was quoted as warning meanwhile that RHJ would not necessarily receive government backing for its approach.

“The public guarantee negotiated with Magna does not automatically apply to the financial investor RHJ,” Koch told the Handelsblatt business daily.

BAIC plans to invest in Opel in China to ramp up production there by 2015, according to a document dated 2 July seen by Dow Jones Newswires.

BAIC is offering $990m in equity for a 51% stake in Opel, with GM retaining 49 percent.

RHJ on Monday announced in a statement that talks with GM were at an “advanced stage,” but didn’t offer further details.