DETROIT  A Chinese automaker has expressed interest in buying a stake in General Motors when it holds a public stock offering later this year, a move that could raise concerns about foreign influence over the largest American automaker.

The Shanghai-based company, the SAIC Motor Corporation, has had a longtime partnership with G.M. in China.

An SAIC spokeswoman, Zhu Xiangjun, said Monday that comments about a possible G.M. stake were made last month by SAIC’s chairman, Hu Maoyuan. She said his comments remained the company’s position but declined further comment.

“G.M. is our important strategic partner,” Mr. Hu said in August. “We are not clear about the details of its I.P.O. We will make the right decision when we know the details.”