SHANGHAI -- General Motors could finalize the sale of its German auto unit Opel as early as this week, the U.S. automaker's CEO said Tuesday, according to The Associated Press.

Fritz Henderson, visiting China for the first time since GM was restructured last summer, was also upbeat about the prospects for the sale of the company's Hummer unit to Chinese buyer Sichuan Tengzhong Heavy Industrial Machinery Corp., which is still awaiting Chinese government approval.

Despite labor union objections over possible job losses, the sale of GM's Opel and Vauxhall units to Canadian autoparts supplier Magna International Inc. is expected to go ahead, Henderson told reporters.

Magna along with Russia's state-owned Sberbank agreed to buy a 65 percent stake in Opel from General Motors Co. last month. GM is retaining a 35 percent stake.

"It's quite possible that you'll see documents signed this week," Henderson said.