Last week, GM Europe submitted a rescue plan for Opel under which the German unit along with UK-based Vauxhall would be partly spun off.
Germany: GM employed a workforce of 25,000 in 2007
Spain: More than 7,200 employed, GM has been here for 30 years
Sweden: Nearly 5,000 workers
Britain: 4,900 employed
Poland: More than 4,000 jobs
Belgium: 3,700 employed
It said the independent unit would need $4.2bn in state aid.
Karl-Theodor zu Guttenberg, Germany's economy minister, met Opel and GM executives on Friday and said it would take several weeks to decide whether to give state aid.
A spokeswoman for GM UK said the group would be in contact with the British government about its potential role in the future of Vauxhall, which has 5,000 workers in two plants and which has so far insisted it does not need state funds.
The British government pledged $3.3bn in loans to its car industry earlier this year, but manufacturers and industry bodies have complained that they have not been told how to access the money.
Industry representatives are due to meet Peter Mandelson, Britain's business secretary, next week in an open seminar to discuss the issue.
GM's Swedish brand Saab has already sought protection from creditors.
On Thursday, the European Union's executive called for a meeting of member states affected by GM, saying the car-maker was not properly informing the bloc of its problems.
At a news conference, Guenter Verheugen, the EU industry commissioner, said that the way GM was "dealing with the issue of Europe is not acceptable".
Verheugen said: "We expect GM to disclose everything. What are their plans with their European daughter companies and locations?
"What are they doing with property rights, and especially is GM prepared to maintain responsibility for the European companies or not?"
Klaus Franz, GM Europe's senior labour leader, lashed out at management, accusing executives of outbidding each other on job cut targets and scaring away politicians who didn't want to be seen using taxpayer money to fund large-scale staff reductions.