German chancellor Angela Merkel's government is becoming more willing to give General Motors' Opel a state guarantee if a private investor is found, local media reported on Thursday.

"It is looking a lot better than it did four weeks ago," major daily Bild quoted a coalition source as saying.

Progress in talks with potential Opel investors was one of the main reasons for the more positive attitude, the paper said, according to Reuters. Rising car sales were also helping.

Merkel has said Opel needs to sell a sizeable stake to a private investor before her government will sign off on EUR3.3bn in loan guarantees.

GM chief executive Fritz Henderson last Friday revealed the automaker had sent out confidentiality agreements to more than six potential investors for its Opel/Vauxhall unit.

Private equity firms are shunning an Opel stake though, leaving sovereign wealth funds from the Middle East or Asia as the most interested private investors, managers at buyout firms have told Reuters.

Germany's Rheinische Post, citing government sources, reported that a Magna/Gaz consortium had also shown interest in taking a stake.