The head of GM Europe has said he hopes German carmaker Opel will be bought by Magna by mid-July adding that the Canadian firm has a "considerable lead" on other possible buyers, a report said Saturday.

"The only thing remaining is for the details to be agreed" between the two businesses, said Carl-Peter Forster in an interview due appear in the Sunday newspaper Frankfurter Allegemeine Zeitung.

"After the meeting of the leaders of General Motors (GM.UL) and Magna, I am absolutely convinved that there will be an agreement," he said.

He did not specify a date for the signing of the contract but said "it would be great if could be done between now and mid-July."

The German government last month announced a rescue plan for Opel in which 35 percent of the firm would go to the Russian state bank Sberbank, 20 percent would go to Canadian auto parts manufacturer Magna International and 35 percent would stay with GM.