"The chancellor has made it clear that she is ready, where necessary, to conduct negotiations herself. Until now, these negotiations have been led by the ministries concerned," spokesman Ulrich Wilhelm told a regular briefing.
Wilhelm reiterated that Berlin's preference is for a bid by Canadian auto parts maker Magna - which is backed by Russian state-owned Sberbank - over a rival bid from Brussels-based investment firm RHJ International.
While the final decision lies with GM, the German government is involved as it is set to stump up billions of euros in loan guarantees to sweeten any takeover deal in a bid to save tens of thousands of jobs.
"The situation is unchanged" as regards the situation in the negotiations between the various parties, Wilhelm added.
In late July, the authorities in Berlin said a final decision on who would win the bidding war for Opel would probably not be taken for several months. While Berlin prefers Magna because it fears RHJ would slash jobs, GM has expressed a preference for the RHJ bid.
US President Barack Obama's administration, which holds a majority stake in GM, has said it will not get involved in the talks.