Opel is in talks with the German government about a cash injection of 3.3 billion euros ($US4.16 billion) from the government.
The company, which is owned by General Motors, announced last week that it needed the money to avert job losses and closures of car plants.
Economy minister Karl-Theodor zu Guttenberg said he would not be rushed into making a decision about state aid.
The BBC reports that like most carmakers, Opel is suffering from a slump in sales.
Mr Guttenberg said the government would carry out "a very far-reaching examination" of Opel's proposals.
GM Europe proposed last week that Opel should be partly separated from its parent company's US operations.