The German government is now looking to General Motors and the US administration for help to answer remaining questions over the future of GM’s European unit Opel.

German economy minister Karl-Theodor zu Guttenberg is in the US for talks with the automaker and government.

Before leaving Germany at the weekend, he reiterated that GM Europe’s Opel rescue plan had left too many questions unanswered.

“I hope GM and the US government will be ready to shed some light on the issue,” Guttenberg told Reuters .

GM Europe’s rescue plan, submitted to the German government last month, would see Opel and UK unit Vauxhall partly spun off into a new subsidiary which would need EUR3.3bn of state aid.

Since then, there has been considerable debate amongst the various political parties and regions in Germany on how to aid Opel, or not, and if aid is granted, in what form.

German chancellor Angela Merkel has said her government would only help companies such as Opel if it would secure their future and not just evaporate without any effect. Such aid should also not find its way to GM coffers in the US.

Merkel also has said that any decision on German government help for Opel depended on decisions the US administration made on aid to parent General Motors, Reuters noted.

In a radio interview on Sunday, Merkel said Guttenberg had to assess in his US talks this week to what extent General Motors could grant Opel more liberties.

“If we then manage to find an investor who makes clear he sees positive prospects for Opel in a European network, we will be able to see whether we can help with normal government instruments, such as guarantees,” she told Deutschlandfunk.

Roland Koch, state premier of the western state of Hesse where Opel has a large factory, earlier expressed a positive view on the rescue plan the company had provided.

Merkel was quoted recently as saying Opel was not ‘systemically’ essential to the future of Germany.