RPT-German economy minister says Opel insolvency possible

(Fixes typo in headline)

BERLIN, June 16 (Reuters) - Carmaker Opel could still face insolvency despite a preliminary deal the German government struck to rescue General Motors' European unit, German Economy Minister Karl-Theodor zu Guttenberg said on Tuesday.

"All of that could still happen," Guttenberg said in reference to possible insolvency at an event in Berlin.

Guttenberg had previously refused to rule out the insolvency of the carmaker, which employs around 25,000 in Germany, and has plants in Britain, Spain, Poland and Austria.

Last month, the German government struck a preliminary agreement with Canadian auto parts group Magna MGa.TO for a takeover of Opel, though Berlin has said repeatedly since then that other investors interested in Opel remain in the running.

Opel's U.S. parent General Motors GMGMQ.PK filed for bankruptcy protection at the start of this month.

Magna's co-Chief Executive Donald Walker said on Tuesday his company must address several issues in completing the Opel takeover including ensuring there was a "complete firewall" between the auto parts business and the carmaking side. (Reporting by Gernot Heller, writing by Dave Graham, editing by Leslie Gevirtz)